Separate and joint effects of arginine and glucose on ovine fetal
insulin secretion.
Gresores, Adrian, Susan Anderson, David Hood, Gary O. Zerbe, William
W. Hay.
Departments of Pediatrics, and Preventive Medicine and Biometrics,
University of Colorado Health Sciences Center, Denver, CO 80262
APStracts 3:0177E, 1996.
To determine separate and joint effects of increases (_) in fetal
plasma concentrations of arginine (Af) and glucose (Gf) on fetal
insulin (If) secretion (_If), 15 late-gestation fetal sheep were
given 5 minute arginine bolus infusions (40, 86, 144, 201, and 402
[mu]mol/kg estimated fetal weight) at 90 minutes of 120 minute steady
state glucose clamps (Basal Gf, Basal+0.6mM Gf, and Basal+1.1mM Gf),
producing absolute and percent increases above basal Af of 25.8+/
-1.3[mu]M (+33%), 50.9+/-6.3[mu]M (+66%), 83.8+/-7.1[mu]M (+108%),
122.1+/-9.4[mu]M (+156%), and 302.2+/-28.2[mu]M (+386%),
respectively. Acute hyperglycemia alone produced an increase above
basal If of 9+/-1[mu]U/mL (+80%) and 19+/-2[mu]U/mL (+170%) after
B+0.6 and B+1.1mM Gf, respectively. Increasing values of _Af showed
separate but lesser effects on _If which were significant only at
very high values of Af (>100% above mean normal Af) unless
marked hyperglycemia (1.5 to 2-fold normal) also was present,
demonstrating joint effects of _Af and _Gf on _If according to a best
fit inverse polynomial response surface. We conclude that
physiological increases in Af at normal glucose concentrations are
not a potent stimulus to insulin secretion in fetal sheep.
Received 27 February 1996; accepted in final form 14 August 1996.
APS Manuscript Number E104-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 August 1996