| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1
Direct evidence for leptin resistance in peripheral tissues such as skeletal muscle does not exist. Therefore, we investigated the effects of different high-fat diets on lipid metabolism in isolated rat soleus muscle and specifically explored whether leptin's stimulatory effects on muscle lipid metabolism would be reduced after exposure to high-fat diets. Control (Cont, 12% kcal fat) and high-fat [60% kcal safflower oil (n-6) (HF-Saff); 48% kcal safflower oil plus 12% fish oil (n-3)] diets were fed to rats for 4 wk. After the dietary treatments, muscle lipid turnover and oxidation in the presence and absence of leptin was measured using pulse-chase procedures in incubated resting soleus muscle. In the absence of leptin, phospholipid, diacylglycerol, and triacylglycerol (TG) turnover were unaffected by the high-fat diets, but exogenous palmitate oxidation was significantly increased in the HF-Saff group. In Cont rats, leptin increased exogenous palmitate oxidation (21.4 ± 5.7 vs. 11.9 ± 1.61 nmol/g, P = 0.019) and TG breakdown (39.8 ± 5.6 vs. 27.0 ± 5.2 nmol/g, P = 0.043) and decreased TG esterification (132.5 ± 14.6 vs. 177.7 ± 29.6 nmol/g, P = 0.043). However, in both high-fat groups, the stimulatory effect of leptin on muscle lipid oxidation and hydrolysis was eliminated. Partial substitution of fish oil resulted only in the restoration of leptin's inhibition of TG esterification. Thus we hypothesize that, during the development of obesity, skeletal muscle becomes resistant to the effects of leptin, resulting in the accumulation of intramuscular TG. This may be an important initiating step in the development of insulin resistance common in obesity.
pulse-chase; fatty acid oxidation; triacylglycerol; hydrolysis; esterification
This article has been cited by other articles:
|
|
 |
|
  R. C. Noland, J. P. Thyfault, S. T. Henes, B. R. Whitfield, T. L. Woodlief, J. R. Evans, J. A. Lust, S. L. Britton, L. G. Koch, R. W. Dudek, et al. Artificial selection for high-capacity endurance running is protective against high-fat diet-induced insulin resistance Am J Physiol Endocrinol Metab, July 1, 2007; 293(1): E31 - E41. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. L. Mullen, A. C. Smith, K. A. Junkin, and D. J. Dyck Globular adiponectin resistance develops independently of impaired insulin-stimulated glucose transport in soleus muscle from high-fat-fed rats Am J Physiol Endocrinol Metab, July 1, 2007; 293(1): E83 - E90. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Guerra, A. Santana, T. Fuentes, S. Delgado-Guerra, A. Cabrera-Socorro, C. Dorado, and J. A. L. Calbet Leptin receptors in human skeletal muscle J Appl Physiol, May 1, 2007; 102(5): 1786 - 1792. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. A. Collier, C. R. Bruce, A. C. Smith, G. Lopaschuk, and D. J. Dyck Metformin counters the insulin-induced suppression of fatty acid oxidation and stimulation of triacylglycerol storage in rodent skeletal muscle Am J Physiol Endocrinol Metab, July 1, 2006; 291(1): E182 - E189. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Hajnal, M. Covasa, and N. T. Bello Altered taste sensitivity in obese, prediabetic OLETF rats lacking CCK-1 receptors Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2005; 289(6): R1675 - R1686. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. W. Petersen, A. L. Carey, M. Sacchetti, G. R. Steinberg, S. L. Macaulay, M. A. Febbraio, and B. K. Pedersen Acute IL-6 treatment increases fatty acid turnover in elderly humans in vivo and in tissue culture in vitro Am J Physiol Endocrinol Metab, January 1, 2005; 288(1): E155 - E162. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. R. Bruce and D. J. Dyck Cytokine regulation of skeletal muscle fatty acid metabolism: effect of interleukin-6 and tumor necrosis factor-{alpha} Am J Physiol Endocrinol Metab, October 1, 2004; 287(4): E616 - E621. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. R. Commerford, L. Peng, J. J. Dube, and R. M. O'Doherty In vivo regulation of SREBP-1c in skeletal muscle: effects of nutritional status, glucose, insulin, and leptin Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2004; 287(1): R218 - R227. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. R. Steinberg, A. C. Smith, S. Wormald, P. Malenfant, C. Collier, and D. J. Dyck Endurance training partially reverses dietary-induced leptin resistance in rodent skeletal muscle Am J Physiol Endocrinol Metab, January 1, 2004; 286(1): E57 - E63. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. G. Ramsay Porcine leptin inhibits lipogenesis in porcine adipocytes J Anim Sci, December 1, 2003; 81(12): 3008 - 3017. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. G. Ramsay Porcine leptin inhibits protein breakdown and stimulates fatty acid oxidation in C2C12 myotubes J Anim Sci, December 1, 2003; 81(12): 3046 - 3051. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Shimizu, M. Yamazaki, K. Nakanishi, M. Sakurai, A. Sanada, T. Takewaki, and K. Tonosaki Enhanced Responses of the Chorda Tympani Nerve to Sugars in the Ventromedial Hypothalamic Obese Rat J Neurophysiol, July 1, 2003; 90(1): 128 - 133. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. W. Hulver, J. R. Berggren, R. N. Cortright, R. W. Dudek, R. P. Thompson, W. J. Pories, K. G. MacDonald, G. W. Cline, G. I. Shulman, G. L. Dohm, et al. Skeletal muscle lipid metabolism with obesity Am J Physiol Endocrinol Metab, April 1, 2003; 284(4): E741 - E747. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. K. Roberts, J. J. Berger, and R. J. Barnard Long-term effects of diet on leptin, energy intake, and activity in a model of diet-induced obesity J Appl Physiol, September 1, 2002; 93(3): 887 - 893. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. R. Steinberg, M. L. Parolin, G. J. F. Heigenhauser, and D. J. Dyck Leptin increases FA oxidation in lean but not obese human skeletal muscle: evidence of peripheral leptin resistance Am J Physiol Endocrinol Metab, July 1, 2002; 283(1): E187 - E192. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. R. Steinberg, D. J. Dyck, J. Calles-Escandon, N. N. Tandon, J. J. F. P. Luiken, J. F. C. Glatz, and A. Bonen Chronic Leptin Administration Decreases Fatty Acid Uptake and Fatty Acid Transporters in Rat Skeletal Muscle J. Biol. Chem., March 8, 2002; 277(11): 8854 - 8860. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Lau, W. D. Blinn, A. Bonen, and D. J. Dyck Stimulatory effects of leptin and muscle contraction on fatty acid metabolism are not additive Am J Physiol Endocrinol Metab, July 1, 2001; 281(1): E122 - E129. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. R. Steinberg, A. Bonen, and D. J. Dyck Fatty acid oxidation and triacylglycerol hydrolysis are enhanced after chronic leptin treatment in rats Am J Physiol Endocrinol Metab, March 1, 2002; 282(3): E593 - E600. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
