AJP - Endo Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Endocrinol Metab 294: E365-E370, 2008. First published December 4, 2007; doi:10.1152/ajpendo.00639.2007
0193-1849/08 $8.00
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
294/2/E365    most recent
00639.2007v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Rozance, P. J.
Right arrow Articles by Hay, W. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Rozance, P. J.
Right arrow Articles by Hay, W. W., Jr.

Chronic late-gestation hypoglycemia upregulates hepatic PEPCK associated with increased PGC1{alpha} mRNA and phosphorylated CREB in fetal sheep

Paul J. Rozance,1 Sean W. Limesand,2 James S. Barry,1 Laura D. Brown,1 Stephanie R. Thorn,1 Dan LoTurco,1 Timothy R. H. Regnault,1,3 Jacob E. Friedman,1 and William W. Hay, Jr.1

1Perinatal Research Center, Department of Pediatrics, School of Medicine, University of Colorado Denver and Health Sciences Center, Aurora, Colorado; 2Agricultural Research Complex, Department of Animal Sciences, University of Arizona, Tucson, Arizona; and 3Department of Obstetrics and Gynaecology, University of Western Ontario, London, Ontario, Canada

Submitted 2 October 2007 ; accepted in final form 29 November 2007


   ABSTRACT
TOP
 ABSTRACT
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Hepatic glucose production is normally activated at birth but has been observed in response to experimental hypoglycemia in fetal sheep. The cellular basis for this process remains unknown. We determined the impact of 2 wk of fetal hypoglycemia during late gestation on enzymes responsible for hepatic gluconeogenesis, focusing on the insulin-signaling pathway, transcription factors, and coactivators that regulate gluconeogenesis. Hepatic phosphoenolpyruvate carboxykinase and glucose-6-phosphatase mRNA increased 12-fold and 7-fold, respectively, following chronic hypoglycemia with no change in hepatic glycogen. Chronic hypoglycemia decreased fetal plasma insulin with no change in glucagon but increased plasma cortisol 3.5-fold. Peroxisome proliferator-activated receptor-{gamma} coactivator-1{alpha} mRNA and phosphorylation of cAMP response element binding protein at Ser133 were both increased, with no change in Akt, forkhead transcription factor FoxO1, hepatocyte nuclear factor-4{alpha}, or CCAAT enhancer binding protein-β. These results demonstrate that chronic fetal hypoglycemia triggers signals that can activate gluconeogenesis in the fetal liver.

glucose; gluconeogenesis; cortisol; cAMP response element binding protein; peroxisome proliferator-activated receptor-{gamma} coactivator-1{alpha}; phosphoenolpyruvate carboxykinase

INTRAUTERINE GROWTH RESTRICTION (IUGR) affects 4–8% of newborns and is commonly associated with placental insufficiency and decreased fetal nutrient delivery (12, 45, 52). In addition to a wide variety of perinatal morbidities, IUGR increases the risk of developing several adult-onset metabolic diseases, including type 2 diabetes mellitus, a disease characterized by peripheral insulin resistance and insufficient insulin secretion (24, 49). One of the hallmarks of type 2 diabetes is reduced ability of insulin to suppress hepatic glucose production (22). It is significant, therefore, that in several animal models of IUGR there is an early and persistent increase in fetal and neonatal hepatic phosphoenolpyruvate carboxykinase (PEPCK) expression, the enzyme that catalyzes the first committed step of gluconeogenesis (9, 21, 32, 42, 47, 65). The various nutrient and secondary metabolic abnormalities in IUGR fetuses that might cause such changes in liver enzyme function and glucose production are uncertain. The most common metabolic condition in all IUGR fetuses that would have direct bearing on hepatic glucose production is decreased placental glucose supply to the fetus and relative fetal hypoglycemia. Studies of experimental fetal hypoglycemia without placental insufficiency or global nutrient restriction, however, have shown variable results for induction of hepatic PEPCK (11, 20, 23, 40, 43), which may reflect species, timing/duration, and other methodological differences.

Among the complex network of transcription factors and cofactors that regulate PEPCK gene expression, peroxisome proliferator-activated receptor-{gamma} coactivator-1{alpha} (PGC1{alpha}) and cAMP response element binding protein (CREB) are particularly important effectors of the cAMP pathway. PGC1{alpha} does not bind directly to the PEPCK promoter. Instead it facilitates the transcriptional activity of hepatocyte nuclear factor (HNF) 4{alpha}, the glucocorticoid receptor, and forkhead transcription factor FoxO1 to increase PEPCK gene transcription (7, 37). CCAAT enhancer binding protein (C/EBP){alpha} and C/EBPβ bind to the cAMP response element of the PEPCK promoter and play an important role in cAMP induction (7, 55). The prevailing model is that induction by cAMP is mediated by phosphorylation of CREB, which must interact with C/EBP and other factors bound to an upstream accessory enhancer to stimulate gene transcription (25, 38). Furthermore, CREB induces PGC1{alpha} mRNA expression (37). FoxO1, which is negatively regulated by insulin signaling through Akt via nuclear exclusion, also facilitates PEPCK gene expression (7).

To evaluate the impact of experimental hypoglycemia on fetal glucose metabolism, we previously used late-gestation hypoglycemic fetal sheep produced by a continuous maternal insulin infusion (10). This renders the fetus chronically hypoglycemic, and these fetal sheep increase endogenous glucose production, but the cellular basis for this response is unknown. Given the propensity for increased glucose production and its contribution to the risk for type 2 diabetes among IUGR offspring, it is important to understand the cellular mechanisms responsible for increased hepatic glucose production in response to fetal hypoglycemia.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Animal model and organ isolation. Studies were conducted in pregnant Columbia-Rambouillet ewes (singleton) during the final 20% of gestation (term of 147 days). Indwelling catheters were surgically placed into the ewe and fetus as previously described (34, 56). All animal procedures were in compliance with guidelines of the United States Department of Agriculture, the National Institutes of Health, and the American Association for the Accreditation of Laboratory Animal Care. The animal care and use protocols were approved by the University of Colorado Health Sciences Center Institutional Animal Care and Use Committee. Data for many of the animals used in this study have been reported, as described in RESULTS (34, 56). As previously described, animals were randomly placed into one of two groups: euglycemic control (C) animals (n = 15) or hypoglycemic (H) animals (n = 16). The H ewes received a 2-wk intravenous insulin infusion (30–60 pmol·min–1·kg–1, Humulin R; Eli Lilly, Indianapolis, IN) in 0.5% BSA (Sigma, St. Louis, MO) in 0.9% NaCl adjusted on average twice daily to produce a 50% reduction in maternal plasma glucose (from 60–70 to 30–35 mg/dl), which also decreased fetal glucose concentrations by 50%. The insulin infusion was started on day 122.5 ± 0.6 of gestation. Gestational ages at necropsy are given in Table 1.


View this table:
[in this window]
[in a new window]

  		Table 1. Fetal characteristics

 
Necropsies were performed as follows: the ewe and fetus were anesthetized with maternally administered intravenous ketamine (4.4 mg/kg) and diazepam (0.11 mg/kg). After ewes were hysterectomized, the fetus was removed, weighed, and dissected for organ weights. Sections of the right hepatic lobe were snap frozen in liquid nitrogen and then transferred to a –80°C freezer. The ewe was then euthanized by administering intravenous concentrated pentobarbital sodium (10 ml; Sleepaway, Fort Dodge Animal Health, Fort Dodge, IA). The fetus died under anesthesia following an intracardiac injection of pentobarbital sodium (1 ml).

Biochemical analysis. Whole blood was collected in EDTA-coated syringes and was centrifuged (14,000 g) for 3 min at 4°C. Plasma was removed, and the glucose and lactate concentrations were determined by using the YSI model 2700 select biochemistry analyzer (Yellow Springs Instruments, Yellow Springs, OH). The remainder of the plasma was stored at –70°C for hormone measurements. Plasma insulin concentrations were measured by an ovine insulin ELISA (Alpco, Windham, NH; inter- and intra-assay coefficients of variation were 2.9 and 5.6%, respectively), and plasma cortisol concentrations were measured by a salivary cortisol ELISA (Alpco; inter- and intra-assay coefficients of variation were 5.7 and 4.4%, respectively). Blood oxygen content was determined by using an ABL 520 blood gas analyzer (Radiometer, Copenhagen, Denmark) (36).

Glycogen content. Hepatic glycogen content was determined as previously described, and results are expressed as milligrams of glycogen per gram liver (wet weight) (2).

Cloning and real-time PCR for relative gene expression. Total RNA was extracted from pulverized hepatic tissue (100 mg) and was reverse transcribed into cDNA as previously described (35). Cloning and real-time quantitative PCR for ovine ribosomal protein S15, PEPCK, glucose-6-phosphatase (G6Pase), and PGC1{alpha} (GenBank accession nos. AY949774, EF062862, EF062861, and AY957611, respectively) have been previously described (35, 57). cDNA samples were run in triplicate, and the quantitative PCR was performed as previously described (57) with the standard curve method of relative quantification used to compare results (66). S15 was used as a housekeeping gene and was not different between groups.

Protein extraction and Western blot analysis. Protein was extracted from pulverized hepatic tissue (200 mg) by the addition of 600 µl of ice-cold lysis buffer [150 mmol/l NaCl, 20 mmol/l Tris (pH 7.4), 1% vol/vol Nonidet P-40, 2 mmol/l EDTA, 2.5 mmol/l Na4P2O7, 10% vol/vol glycerol, 20 mmol/l β-glycerophosphate, 0.575 mmol/l phenylmethylsulfonyl fluoride, 2% vol/vol Sigma mammalian protease inhibitor cocktail, and 0.5% vol/vol Sigma phosphatase inhibitor] followed by 30 min on an orbital rocker at 4°C. The samples were then sonicated for 30 s, agitated, and placed on an orbital rocker for another 30 min at 4°C. The protein was separated from cellular debris by centrifugation at 21,000 g for 20 min at 4°C. The supernatant was removed, and the protein concentration was quantified with the BioRad DC protein assay (BioRad, Hercules, CA).

Equal amounts of protein were separated by polyacrylamide gel electrophoresis under reduced conditions (5% β-mercaptoethanol). Proteins were then transferred to a polyvinylidene difluoride membrane (Bio-Rad). Unless otherwise noted, all Western blot membranes were blocked for 1 h in phosphate-buffered saline with 0.1% Tween 20 (PBST; Bio-Rad) and 5% wt/vol nonfat dried milk (NFDM) for 1 h at room temperature. The following primary antibodies were diluted in PBST with 5% NFDM: C/EBPβ (1:1,000, Santa Cruz Biotechnology, Santa Cruz, CA), CREB (1:1,000, Santa Cruz Biotechnology), HNF4{alpha} (1:750, Santa Cruz Biotechnology), and β-actin (1:40,000, Medimmune, Gaithersburg, MD). Other primary antibodies were diluted in PBST with 5% BSA: Ser133-phosphorylated CREB (1:500, Cell Signaling Technology, Danvers, MA), Akt (1:500, Cell Signaling Technology), Ser473-phosphorylated Akt (1:500, Cell Signaling Technology), FoxO1 (1:250, Cell Signaling Technology), and Ser256-phosphorylated FoxO1 (1:500, Cell Signaling Technology). Membranes probed for insulin receptor β were blocked for 1 h at room temperature in PBST with 5% NFDM and with 1% BSA, and the primary antibody (Santa Cruz Biotechnology) was diluted 1:1,250 in the same buffer. Horseradish peroxidase-conjugated secondary antibodies were diluted in PBST with 5% NFDM and were applied to membranes for 1 h at room temperature. Immunocomplexes were detected with enhanced chemiluminescence (ECL Plus, Amersham, Piscataway, NJ). Densitometry was performed by using Scion Image software (Scion, Frederick, MD). All results were normalized to β-actin to control for loading differences, and a reference sample was analyzed on every membrane to control for differences in transfer efficiency. Ser473-phosphorylated Akt and Ser256-phosphorylated FoxO1 also were normalized to the total amount of each protein. Antibodies were stripped from the membranes with Restore Western stripping buffer (Pierce, Rockford, IL).

Statistical analysis. Statistical analysis was performed with SAS version 9.1 (58). All results are presented as means ± SE. Groups were compared by using either the Student's t-test (parametric) or the Mann-Whitney test (nonparametric), both two tailed, and a level of 0.05 or less was considered significant.


   RESULTS
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 GRANTS
 REFERENCES
 
Fetal characteristics. Information on the experimental conditions and necropsy measurements have been previously reported for many of the fetuses used in these experiments (34, 56). Characteristics for the group of fetuses used in this study are summarized in Table 1. We previously reported (34) no difference in fetal arterial plasma glucagon, epinephrine, or norepinephrine concentrations between the groups. Reported here for the first time (Table 1), fetal arterial plasma cortisol concentrations are significantly greater (3.5-fold increase, P < 0.0005) in the H group than in the C group. The percent of male fetuses was not statistically different (60% C, 40% H), and there was no distinguishable effect of fetal sex on any measurements.

G6Pase and PEPCK mRNA expression and glycogen content. PEPCK mRNA was significantly greater (12-fold, P < 0.05) in H fetal livers compared with C fetuses (Fig. 1A). The same expression pattern was found for G6Pase mRNA (7-fold increase, P < 0.0005, Fig. 1B). Chronic fetal hypoglycemia did not affect hepatic glycogen content (Fig. 2).


Figure 1
View larger version (9K):
[in this window]
[in a new window]

  		Fig. 1. Hepatic mRNA concentrations. Phosphoenolpyruvate carboxykinase (PEPCK; A), glucose-6-phosphatase (G6Pase; B), and peroxisome proliferator-activated receptor-{gamma} coactivator-1{alpha} (PGC1{alpha}; C) mRNA concentrations were determined in livers from control and hypoglycemic fetuses by real-time quantitative PCR. Data are means ± SE normalized to ribosomal protein S15 and are presented as fold change relative to control fetuses. Treatment groups are listed on x-axis. *Higher amount of PEPCK (P < 0.05), G6Pase (P < 0.0005), and PGC1{alpha} (P < 0.05) in hypoglycemic livers compared with control livers. All statistics are from Mann-Whitney test for nonparametric analysis.

 

Figure 2
View larger version (6K):
[in this window]
[in a new window]

  		Fig. 2. Hepatic glycogen. Glycogen content (mg/g tissue; means ± SE) was determined for control and hypoglycemic fetuses. No differences were found between treatment groups, which are listed on x-axis.

 
Insulin receptor and Akt. Hepatic content of the β-subunit of the insulin receptor was significantly higher (34% increase) in H fetuses compared with C fetal livers (P < 0.05, Fig. 3, A and B). There were no differences in the hepatic content of Akt (1.00 ± 0.13 C, 0.87 ± 0.09 H, arbitrary units relative to C) or in the ratio of Akt phosphorylated at the serine 473 position to total Akt (1.00 ± 0.23 C, 1.17 ± 0.29 H, arbitrary units relative to C).


Figure 3
View larger version (16K):
[in this window]
[in a new window]

  		Fig. 3. Hepatic protein concentrations. A: representative Western blots for insulin receptor β, cAMP response element binding protein (CREB), Ser133-phosphorylated CREB, and β-actin. B–D: results of Western blot analysis for insulin receptor-β normalized to β-actin (B), CREB normalized to β-actin (C), and Ser133-phosphorylated CREB normalized to total CREB (D). Treatment groups are listed on x-axis. *Higher amount of insulin receptor-β (P < 0.05), higher ratio of Ser133-phosphorylated CREB to total CREB (P < 0.01), and a lower amount of CREB (P < 0.001) in hypoglycemic livers compared with control livers. Statistics are from either Student's t-test (parametric) or Mann-Whitney test (nonparametric).

 
Transcription factors and transcription coactivators CREB, c/EBPβ, HNF4{alpha}, FoxO1, and PGC1{alpha}. There was a significantly lower amount of total CREB (38% decrease) present in H livers compared with C fetal livers (P < 0.001, Fig. 3, A and C). The ratio of phosphorylated (active) CREB on serine 133 to total CREB was twofold higher in H fetal livers compared with C (P < 0.01, Fig. 3, A and D). C/EBPβ (1.00 ± 0.08 C, 1.12 ± 0.12 H, arbitrary units relative to C), HNF4{alpha} (1.00 ± 0.16 C, 0.88 ± 0.17 H, arbitrary units relative to C), FoxO1 (1.00 ± 0.10 C, 0.94 ± 0.11 H, arbitrary units relative to C), and the ratio of FoxO1 phosphorylated at the serine 256 position to total FoxO1 (1.00 ± 0.08 C, 0.77 ± 0.09 H, arbitrary units relative to C) were not different between groups. PGC1{alpha} mRNA was 2.5-fold greater in H compared with C fetal livers (P < 0.05, Fig. 1C).


   DISCUSSION
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
GRANTS
 REFERENCES
 
The major finding in the present study is that fetal glucose deprivation activates hepatic PEPCK and G6Pase mRNA expression. Fetal hypoglycemia does not affect hepatic glycogen content. This demonstrates that fetal glucose production following chronic hypoglycemia is due to sustained gluconeogenesis as previously postulated (10) and not to persistent glycogenolysis. Normally, hepatic gluconeogenesis in fetal sheep does not occur until very late in gestation, when it develops in response to a surge in fetal cortisol secretion, which occurs at gestational ages beyond the time point used in this study (18, 19). The central role of fetal cortisol secretion in activating glucose production has been determined by studies showing that hypophysectomy in fetal sheep renders them incapable of increasing plasma cortisol concentrations. Such fetuses have significantly decreased hepatic activities of gluconeogenic enzymes. Furthermore, fetal cortisol infusions increase these enzyme activities (17, 18). Our data suggest that fetal hypoglycemia increases fetal cortisol production and plasma concentrations and induces both PGC1{alpha} mRNA and phosphorylated CREB, all of which are important regulatory components in the gluconeogenic response.

In our model, glucagon and epinephrine concentrations are not elevated, although the insulin-to-glucagon ratio is decreased (34). Plasma cortisol is higher, and excess glucocorticoids increase PEPCK gene expression directly and act permissively to augment induction by other stimuli (6). Glucagon, a decrease in the insulin-to-glucagon ratio, or epinephrine, activates CREB by stimulating phosphorylation at position 133, which in turn increases expression of the nuclear coactivator PGC1{alpha} as well as directly increasing PEPCK and G6Pase expression (27, 54, 60). Insulin, in contrast, suppresses hepatic PGC1{alpha} transcriptional activity in part via Akt-mediated phosphorylation and nuclear export of the forkhead family activator FoxO1 (50). In addition, insulin has recently been shown to stimulate phosphorylation of PGC1{alpha} directly to inhibit its ability to activate PEPCK gene transcription (33). Given that we found no changes in the distal insulin-signaling targets, either phosphorylated FoxO1 or Akt, our results suggest that the upregulation of PEPCK during hypoglycemia was more likely due to increased activation by cortisol and a decrease in the insulin-to-glucagon ratio through either CREB or PGC1{alpha}, rather than a reduction in insulin signaling.

The increase in PGC1{alpha} mRNA by chronic fetal hypoglycemia is similar to the findings in the bilateral uterine artery ligation model of IUGR in the rat, in which both PGC1{alpha} and PEPCK mRNA are increased (32). In addition to PGC1{alpha}, we also measured other factors that are known to increase PEPCK and G6Pase expression and activity, including C/EBPβ and HNF4{alpha} (5, 8, 53). However, neither of these factors was increased by chronic fetal hypoglycemia. An interesting negative result was no change in HNF4{alpha} because it differs from fetal rats exposed to exogenous glucocorticoids. These fetuses have increased hepatic concentrations of PEPCK and HNF4{alpha} mRNA but normal hepatic concentrations of PGC1{alpha} (41). In our model of fetal hypoglycemia, with increased endogenous fetal glucocorticoids, hepatic PEPCK and PGC1{alpha} mRNA are increased but HNF4{alpha} protein is not different. These differences suggest that the surge in fetal cortisol may not be the sole mechanism upregulating PEPCK in the hypoglycemic fetal sheep.

The maintenance of hepatic glycogen content in the hypoglycemic group, despite a lower insulin concentration and decreased glycogenic precursors (glucose and lactate), confirms the results of some earlier fetal experiments but is in conflict with others. Several experimental models of IUGR and nutrient deprivation have demonstrated decreased hepatic glycogen (4, 39, 43, 44, 46). In each of these models, when reported, fetal oxygen values (partial pressure, hemoglobin-oxygen saturation, or blood oxygen content) either are normal or decreased and fetal plasma glucagon concentration is increased. It is possible that the increased fetal oxygenation in our hypoglycemic group allows for maintenance of hepatic glycogen. When tested in late-gestation fetal sheep, hypoxemia without hypoglycemia decreases fetal hepatic glycogen content (63). Another difference between this model and the models in which hepatic glycogen decreases is that fetal glucagon is not elevated in the hypoglycemic group (34). In a different late-gestation fetal sheep model of nutrient deprivation, fetuses subjected to a five-day maternal fast had significantly lower fetal weight and maternal hepatic glycogen content but did not have different fetal glucagon concentrations or hepatic glycogen contents (29, 59). In addition, piglets did not have lower liver glycogen contents following a maternal fast for the final 7 or 21 days of gestation (15), and unilateral ligation of the uterine artery in guinea pigs produced IUGR fetuses that had increased hepatic glycogen content (31). Our results are consistent with the studies that demonstrate no decrease in hepatic glycogen following fetal nutrient deprivation, but there clearly are variations among studies.

Cortisol is important for hepatic glycogen accumulation, and at gestational ages beyond 135 days, fetal sheep plasma cortisol is almost entirely of fetal origin (26). Increased cortisol concentrations in response to hypoglycemia have been described before in a variety of late-gestation and neonatal mammals (13, 28, 62). In the sheep, like many mammalian species, liver glycogen content increases during the later part of gestation (61). The increase in hepatic glycogen during the last part of gestation is dependent on cortisol (1, 51, 64), and in fact exogenous cortisol can augment and accelerate late-gestation hepatic glycogen synthesis and deposition (3, 16, 30, 64). These results have been confirmed with in vitro studies using fetal liver explants and primary fetal hepatocytes, which show that glucocorticoids are necessary for allowing insulin-stimulated glycogen synthesis and deposition (14, 48, 64).

In conclusion, 2 wk of experimental hypoglycemia in late-gestation fetal sheep increases hepatic PEPCK and G6Pase mRNA and stimulates hepatic glucose output (10). This is associated with increased fetal plasma cortisol concentrations, increased hepatic PGC1{alpha} mRNA, and activation of hepatic CREB. In addition, fetal hepatic glycogen content is maintained despite decreased insulin and glycogen precursors. However, hepatic glucose production was not enough to restore fetal glucose concentrations to normal, indicating that maternal glucose supply to the fetus is a critical factor regulating fetal glucose concentrations.


   GRANTS
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 GRANTS
REFERENCES
 
This work was supported by National Institutes of Health Grants HD-42815, DK-52138, HD-28794, HD-07186, and RR-00069 (all to W. W. Hay Jr.); a National Institutes of Health-Clinical Nutrition Research Unit Pilot and Feasibility Project 2-P30-DK-48520–11 (P. J. Rozance); and The Children's Hospital Research Institute Research Scholar Award (P. J. Rozance). S. W. Limesand was supported by National Institute of Diabetes and Digestive and Kidney Diseases Grant DK-67393. DNA sequencing core services were provided by the Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, which is supported by National Institute of Diabetes and Digestive and Kidney Diseases Grant P30-DK-57516 (J. C. Hutton).


   FOOTNOTES
 

Address for reprint requests and other correspondence: P. J. Rozance, Perinatal Research Center, Dept. of Pediatrics, Univ. of Colorado Health Sciences Center, P.O. Box 6508, MS F441, Aurora, CO 80045 (e-mail: Paul.Rozance{at}UCHSC.edu)

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.


   REFERENCES
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 

  1. Barnes RJ, Comline RS, Silver M. Effect of cortisol on liver glycogen concentrations in hypophysectomized, adrenalectomized and normal foetal lambs during late or prolonged gestation. J Physiol 275: 567–579, 1978.[Abstract/Free Full Text]
  2. Barry JS, Davidsen ML, Limesand SW, Galan HL, Friedman JE, Regnault TRH, Hay WW Jr. Developmental changes in ovine myocardial glucose transporters and insulin signaling following hyperthermia-induced intrauterine fetal growth restriction. Exp Biol Med (Maywood) 231: 566–575, 2006.[Abstract/Free Full Text]
  3. Benito M, Lorenzo M, Medina JM. Relationship between lipogenesis and glycogen synthesis in maternal and foetal tissues during late gestation in the rat. Effect of dexamethasone. Biochem J 204: 865–868, 1982.[Web of Science][Medline]
  4. Bossi E, Greenberg RE. Sources of blood glucose in the rat fetus. Pediatr Res 6: 765–772, 1972.[Web of Science][Medline]
  5. Boustead JN, Stadelmaier BT, Eeds AM, Wiebe PO, Svitek CA, Oeser JK, O'Brien RM. Hepatocyte nuclear factor-4 alpha mediates the stimulatory effect of peroxisome proliferator-activated receptor gamma co-activator-1 alpha (PGC-1 alpha) on glucose-6-phosphatase catalytic subunit gene transcription in H4IIE cells. Biochem J 369: 17–22, 2003.[CrossRef][Web of Science][Medline]
  6. Cassuto H, Kochan K, Chakravarty K, Cohen H, Blum B, Olswang Y, Hakimi P, Xu C, Massillon D, Hanson RW, Reshef L. Glucocorticoids regulate transcription of the gene for phosphoenolpyruvate carboxykinase in the liver via an extended glucocorticoid regulatory unit. J Biol Chem 280: 33873–33884, 2005.[Abstract/Free Full Text]
  7. Chakravarty K, Cassuto H, Reshef L, Hanson RW. Factors that control the tissue-specific transcription of the gene for phosphoenolpyruvate carboxykinase-C. Crit Rev Biochem Mol Biol 40: 129–154, 2005.[CrossRef][Web of Science][Medline]
  8. Croniger CM, Millward C, Yang J, Kawai Y, Arinze IJ, Liu S, Harada-Shiba M, Chakravarty K, Friedman JE, Poli V, Hanson RW. Mice with a deletion in the gene for CCAAT/enhancer-binding protein beta have an attenuated response to cAMP and impaired carbohydrate metabolism. J Biol Chem 276: 629–638, 2001.[Abstract/Free Full Text]
  9. Desai M, Byrne CD, Zhang J, Petry CJ, Lucas A, Hales CN. Programming of hepatic insulin-sensitive enzymes in offspring of rat dams fed a protein-restricted diet. Am J Physiol Gastrointest Liver Physiol 272: G1083–G1090, 1997.[Abstract/Free Full Text]
  10. DiGiacomo JE, Hay WW Jr. Fetal glucose metabolism and oxygen consumption during sustained hypoglycemia. Metabolism 39: 193–202, 1990.[CrossRef][Web of Science][Medline]
  11. Domenech M, Gruppuso PA, Susa JB, Schwartz R. Induction in utero of hepatic glucose-6-phosphatase by fetal hypoinsulinemia. Biol Neonate 47: 92–98, 1985.[Medline]
  12. Economides DL, Nicolaides KH. Blood glucose and oxygen tension levels in small-for-gestational-age fetuses. Am J Obstet Gynecol 160: 385–389, 1989.[Web of Science][Medline]
  13. Edwards LJ, Symonds ME, Warnes KE, Owens JA, Butler TG, Jurisevic A, McMillen IC. Responses of the fetal pituitary-adrenal axis to acute and chronic hypoglycemia during late gestation in the sheep. Endocrinology 142: 1778–1785, 2001.[Abstract/Free Full Text]
  14. Eisen HJ, Goldfine ID, Glinsmann WH. Regulation of hepatic glycogen synthesis during fetal development: roles of hydrocortisone, insulin, and insulin receptors. Proc Natl Acad Sci USA 70: 3454–3457, 1973.[Abstract/Free Full Text]
  15. Ezekwe MO. Effects of maternal starvation on some blood metabolites, liver glycogen, birth weight and survival of piglets. J Anim Sci 53: 1504–1510, 1981.[Abstract/Free Full Text]
  16. Fowden AL, Comline RS, Silver M. The effects of cortisol on the concentration of glycogen in different tissues in the chronically catheterized fetal pig. Q J Exp Physiol 70: 23–35, 1985.[Abstract/Free Full Text]
  17. Fowden AL, Coulson RL, Silver M. Endocrine regulation of tissue glucose-6-phosphatase activity in the fetal sheep during late gestation. Endocrinology 126: 2823–2830, 1990.[Abstract/Free Full Text]
  18. Fowden AL, Mijovic J, Silver M. The effects of cortisol on hepatic and renal gluconeogenic enzyme activities in the sheep fetus during late gestation. J Endocrinol 137: 213–222, 1993.[Abstract/Free Full Text]
  19. Fowden AL, Mundy L, Silver M. Developmental regulation of glucogenesis in the sheep fetus during late gestation. J Physiol 508: 937–947, 1998.[Abstract/Free Full Text]
  20. Freund N, Kervran A, Assan R, Geloso JP, Girard J. Fetal metabolic response to phloridzin-induced hypoglycemia in pregnant rats. Biol Neonate 38: 321–327, 1980.[Web of Science][Medline]
  21. Girard J, Ferre P, Gilbert M, Kervran A, Assan R, Marliss EB. Fetal metabolic response to maternal fasting in the rat. Am J Physiol Endocrinol Metab Gastrointest Physiol 232: E456–E463, 1977.[Abstract/Free Full Text]
  22. Groop LC, Bonadonna RC, DelPrato S, Ratheiser K, Zyck K, Ferrannini E, Defronzo RA. Glucose and free fatty acid metabolism in non-insulin-dependent diabetes mellitus. Evidence for multiple sites of insulin resistance. J Clin Invest 84: 205–213, 1989.[Web of Science][Medline]
  23. Gruppuso PA, Migliori R, Susa JB, Schwartz R. Chronic maternal hyperinsulinemia and hypoglycemia. A model for experimental intrauterine growth retardation. Biol Neonate 40: 113–120, 1981.[Web of Science][Medline]
  24. Hales CN, Barker DJ, Clark PM, Cox LJ, Fall C, Osmond C, Winter PD. Fetal and infant growth and impaired glucose tolerance at age 64. BMJ 303: 1019–1022, 1991.[Abstract/Free Full Text]
  25. Hanson RW, Reshef L. Regulation of phosphoenolpyruvate carboxykinase (GTP) gene expression. Annu Rev Biochem 66: 581–611, 1997.[CrossRef][Web of Science][Medline]
  26. Hennessy DP, Coghlan JP, Hardy KJ, Scoggins BA, Wintour EM. The origin of cortisol in the blood of fetal sheep. J Endocrinol 95: 71–79, 1982.[Abstract/Free Full Text]
  27. Herzig S, Long F, Jhala US, Hedrick S, Quinn R, Bauer A, Rudolph D, Schutz G, Yoon C, Puigserver P, Spiegelman B, Montminy M. CREB regulates hepatic gluconeogenesis through the coactivator PGC-1. Nature 413: 179–183, 2001.[CrossRef][Medline]
  28. Jackson L, Williams FL, Burchell A, Coughtrie MW, Hume R. Plasma catecholamines and the counterregulatory responses to hypoglycemia in infants: a critical role for epinephrine and cortisol. J Clin Endocrinol Metab 89: 6251–6256, 2004.[Abstract/Free Full Text]
  29. Kaneta M, Liechty EA, Moorehead HC, Lemons JA. Ovine fetal and maternal glycogen during fasting. Biol Neonate 60: 215–220, 1991.[Web of Science][Medline]
  30. Klepac R. Effect of dexamethasone on glycogen deposition in pregnant rats and their fetuses. Exp Clin Endocrinol 86: 305–309, 1985.[Web of Science][Medline]
  31. Lafeber HN, Rolph TP, Jones CT. Studies on the growth of the fetal guinea pig. The effects of ligation of the uterine artery on organ growth and development. J Dev Physiol 6: 441–459, 1984.[Web of Science][Medline]
  32. Lane RH, MacLennan NK, Hsu JL, Janke SM, Pham TD. Increased hepatic peroxisome proliferator-activated receptor-gamma coactivator-1 gene expression in a rat model of intrauterine growth retardation and subsequent insulin resistance. Endocrinology 143: 2486–2490, 2002.[Abstract/Free Full Text]
  33. Li X, Monks B, Ge Q, Birnbaum MJ. Akt/PKB regulates hepatic metabolism by directly inhibiting PGC-1[agr] transcription coactivator. Nature 447: 1012–1016, 2007.[CrossRef][Medline]
  34. Limesand SW, Hay WW Jr. Adaptation of ovine fetal pancreatic insulin secretion to chronic hypoglycaemia and euglycaemic correction. J Physiol 547: 95–105, 2003.[Abstract/Free Full Text]
  35. Limesand SW, Rozance PJ, Smith D, Hay J. Increased insulin sensitivity and maintenance of glucose utilization rates in fetal sheep with placental insufficiency and intrauterine growth restriction. Am J Physiol Endocrinol Metab 293: E1716–E1725, 2007.[Abstract/Free Full Text]
  36. Limesand SW, Rozance PJ, Zerbe GO, Hutton JC, Hay WW Jr. Attenuated insulin release and storage in fetal sheep pancreatic islets with intrauterine growth restriction. Endocrinology 147: 1488–1497, 2006.[Abstract/Free Full Text]
  37. Lin J, Handschin C, Spiegelman BM. Metabolic control through the PGC-1 family of transcription coactivators. Cell Metab 1: 361–370, 2005.[CrossRef][Web of Science][Medline]
  38. Mayr B, Montminy M. Transcriptional regulation by the phosphorylation-dependent factor CREB. Nat Rev Mol Cell Biol 2: 599–609, 2001.[CrossRef][Web of Science][Medline]
  39. Miettinen EL, Kliegman RM. Fetal and neonatal responses to extended maternal canine starvation. II. Fetal and neonatal liver metabolism. Pediatr Res 17: 639–644, 1983.[Web of Science][Medline]
  40. Narkewicz MR, Carver TD, Hay WW Jr. Induction of cytosolic phosphoenolpyruvate carboxykinase in the ovine fetal liver by chronic fetal hypoglycemia and hypoinsulinemia. Pediatr Res 33: 493–496, 1993.[Web of Science][Medline]
  41. Nyirenda MJ, Dean S, Lyons V, Chapman KE, Seckl JR. Prenatal programming of hepatocyte nuclear factor 4alpha in the rat: a key mechanism in the ‘foetal origins of hyperglycaemia’? Diabetologia 49: 1412–1420, 2006.[CrossRef][Web of Science][Medline]
  42. Nyirenda MJ, Lindsay RS, Kenyon CJ, Burchell A, Seckl JR. Glucocorticoid exposure in late gestation permanently programs rat hepatic phosphoenolpyruvate carboxykinase and glucocorticoid receptor expression and causes glucose intolerance in adult offspring. J Clin Invest 101: 2174–2181, 1998.[Web of Science][Medline]
  43. Ogata ES, Paul RI, Finley SL. Limited maternal fuel availability due to hyperinsulinemia retards fetal growth and development in the rat. Pediatr Res 22: 432–437, 1987.[Web of Science][Medline]
  44. Ogata ES, Bussey ME, Finley S. Altered gas exchange, limited glucose and branched chain amino acids, and hypoinsulinism retard fetal growth in the rat. Metabolism 35: 970–977, 1986.[CrossRef][Web of Science][Medline]
  45. Paolini CL, Marconi AM, Ronzoni S, Di Noio M, Fennessey PV, Pardi G, Battaglia FC. Placental transport of leucine, phenylalanine, glycine, and proline in intrauterine growth-restricted pregnancies. J Clin Endocrinol Metab 86: 5427–5432, 2001.[Abstract/Free Full Text]
  46. Parimi PS, Croniger CM, Leahy P, Hanson RW, Kalhan SC. Effect of reduced maternal inspired oxygen on hepatic glucose metabolism in the rat fetus. Pediatr Res 53: 325–332, 2003.[Web of Science][Medline]
  47. Peterside IE, Selak MA, Simmons RA. Impaired oxidative phosphorylation in hepatic mitochondria in growth-retarded rats. Am J Physiol Endocrinol Metab 285: E1258–E1266, 2003.[Abstract/Free Full Text]
  48. Plas C, Duval D. Dexamethasone binding sites and steroid-dependent stimulation of glycogenesis by insulin in cultured fetal hepatocytes. Endocrinology 118: 587–594, 1986.[Abstract/Free Full Text]
  49. Polonsky KS, Sturis J, Bell GI. Non-insulin-dependent diabetes mellitus—a genetically programmed failure of the beta cell to compensate for insulin resistance. N Engl J Med 334: 777–783, 1996.[Free Full Text]
  50. Puigserver P, Rhee J, Donovan J, Walkey CJ, Yoon JC, Oriente F, Kitamura Y, Altomonte J, Dong H, Accili D, Spiegelman BM. Insulin-regulated hepatic gluconeogenesis through FOXO1-PGC-1alpha interaction. Nature 423: 550–555, 2003.[CrossRef][Medline]
  51. Randall GC. Tissue glycogen concentrations in hypophysectomized pig fetuses following infusion with cortisol. J Dev Physiol 10: 77–83, 1988.[Web of Science][Medline]
  52. Resnik R, Creasy R. Intrauterine growth restriction. In: Maternal-Fetal Medicine, edited by Creasy R, Resnik R, Iams J. Philadelphia: Saunders, 2004, p. 495–512.
  53. Rhee J, Inoue Y, Yoon JC, Puigserver P, Fan M, Gonzalez FJ, Spiegelman BM. Regulation of hepatic fasting response by PPARgamma coactivator-1alpha (PGC-1): requirement for hepatocyte nuclear factor 4alpha in gluconeogenesis. Proc Natl Acad Sci USA 100: 4012–4017, 2003.[Abstract/Free Full Text]
  54. Roesler WJ. What is a cAMP response unit? Mol Cell Endocrinol 162: 1–7, 2000.[CrossRef][Web of Science][Medline]
  55. Roesler WJ. The role of C/EBP in nutrient and hormonal regulation of gene expression. Annu Rev Nutr 21: 141–165, 2001.[CrossRef][Web of Science][Medline]
  56. Rozance PJ, Limesand SW, Hay WW Jr. Decreased nutrient-stimulated insulin secretion in chronically hypoglycemic late-gestation fetal sheep is due to an intrinsic islet defect. Am J Physiol Endocrinol Metab 291: E404–E411, 2006.[Abstract/Free Full Text]
  57. Rozance PJ, Limesand SW, Zerbe GO, Hay WW Jr. Chronic fetal hypoglycemia inhibits the later steps of stimulus-secretion coupling in pancreatic beta-cells. Am J Physiol Endocrinol Metab 292: E1256–E1264, 2007.[Abstract/Free Full Text]
  58. SAS Institute. SAS/STAT 9.1 User's Guide. Cary, NC: SAS Institute, 2004.
  59. Schreiner RL, Nolen PA, Bonderman PW, Moorehead HC, Gresham EL, Lemons JA, Escobedo MB. Fetal and maternal hormonal response to starvation in the ewe. Pediatr Res 14: 103–108, 1980.[Web of Science][Medline]
  60. Servillo G, Della Fazia MA, Sassone-Corsi P. Coupling cAMP signaling to transcription in the liver: pivotal role of CREB and CREM. Exp Cell Res 275: 143–154, 2002.[CrossRef][Web of Science][Medline]
  61. Shelley HJ. Glycogen reserves and their changes at birth and in anoxia. Br Med Bull 17: 137–143, 1961.[Free Full Text]
  62. Silver M, Fowden AL. Sympathoadrenal and other endocrine and metabolic responses to hypoglycaemia in the fetal foal during late gestation. Exp Physiol 80: 651–662, 1995.[Abstract]
  63. Stratford LL, Hooper SB. Effect of hypoxemia on tissue glycogen content and glycolytic enzyme activities in fetal sheep. Am J Physiol Regul Integr Comp Physiol 272: R103–R110, 1997.[Abstract/Free Full Text]
  64. Tye LM, Burton AF. Glycogen deposition in fetal mouse tissues and the effect of dexamethasone. Biol Neonate 38: 265–269, 1980.[Web of Science][Medline]
  65. Vuguin P, Raab E, Liu B, Barzilai N, Simmons R. Hepatic insulin resistance precedes the development of diabetes in a model of intrauterine growth retardation. Diabetes 53: 2617–2622, 2004.[Abstract/Free Full Text]
  66. Wong ML, Medrano JF. Real-time PCR for mRNA quantitation. Biotechniques 39: 75–85, 2005.[Web of Science][Medline]



This article has been cited by other articles:


Home page
 Am. J. Physiol. Endocrinol. Metab.Home page
P. J. Rozance, M. M. Crispo, J. S. Barry, M. C. O'Meara, M. S. Frost, K. C. Hansen, W. W. Hay Jr., and L. D. Brown
Prolonged maternal amino acid infusion in late-gestation pregnant sheep increases fetal amino acid oxidation
Am J Physiol Endocrinol Metab, September 1, 2009; 297(3): E638 - E646.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
S. P. Ford, L. Zhang, M. Zhu, M. M. Miller, D. T. Smith, B. W. Hess, G. E. Moss, P. W. Nathanielsz, and M. J. Nijland
Maternal obesity accelerates fetal pancreatic {beta}-cell but not {alpha}-cell development in sheep: prenatal consequences
Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2009; 297(3): R835 - R843.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Endocrinol. Metab.Home page
S. W. Limesand, P. J. Rozance, L. D. Brown, and W. W. Hay Jr.
Effects of chronic hypoglycemia and euglycemic correction on lysine metabolism in fetal sheep
Am J Physiol Endocrinol Metab, April 1, 2009; 296(4): E879 - E887.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
294/2/E365    most recent
00639.2007v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Rozance, P. J.
Right arrow Articles by Hay, W. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Rozance, P. J.
Right arrow Articles by Hay, W. W., Jr.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2008 by the American Physiological Society.