AJP - Endocrinology and Metabolism, Vol 255, Issue 1 E87-E93, Copyright © 1988 by American Physiological Society
Effects of somatostatin and glucose infusion on glucose kinetics in fetal sheep
C. A. Bloch, R. K. Menon and M. A. Sperling
Department of Pediatrics, University of Cincinnati, Ohio 45229.
We examined the contribution of glucose, independently of insulin, on fetal
glucose kinetics in the sheep by infusing somatostatin (SRIF), followed by
SRIF plus glucose (protocol A) or reversing the initial infusion sequence
(protocol B). In protocol A (n = 8), infusion of SRIF at 200 micrograms/h
decreased plasma insulin (IRI) and blood glucose (G) by 2.8 +/- 1.0
microU/ml and 1.34 +/- 0.2 mg/dl from their respective basal concentrations
of 6.8 +/- 1.4 microU/ml and 16.47 +/- 0.91 mg/dl (P less than 0.05; P less
than 0.005). There were no significant changes in plasma glucagon (IRG) or
the rates of umbilical G uptake or of G utilization, but G turnover
decreased by 1.77 +/- 0.34 mg.kg-1.min-1 (P less than 0.005). Addition of G
at a rate of 5.6 +/- 0.8 mg.kg-1.min-1 had no effect on IRI and IRG. Total
G uptake (G infusion rate plus umbilical G uptake) increased from 6.37 +/-
0.77 to 10.25 +/- 1.0 mg.kg-1.min-1 (P less than 0.01), despite suppression
of umbilical G uptake by 33%. Fetal G reached a new steady state of 23.08
+/- 1.37 mg/dl, and G turnover increased by 4.81 +/- 0.96 mg.kg-1.min-1
from its SRIF-induced nadir (P less than 0.005). Since G concentration was
maintained at steady state, the rate of G utilization was equivalent to the
rate of total G uptake, an increase of 60% from basal despite suppressed
IRI.(ABSTRACT TRUNCATED AT 250 WORDS)
