Dietary carbohydrate in neonatal rats affects insulin secretion
from isolated pancreatic islets of adults and progeny.
Laychock, Suzanne G., Satyaprasad Vadlamudi, and Mulchand S. Patel.
Department of Pharmacology and Toxicology, and Department of
Biochemistry, School of Medicine and Biomedical Sciences, State
University of New York at Buffalo, Buffalo, NY 14214
APStracts 2:0109E, 1995.
Neonatal rat pups were artificially reared on isocaloric diets high in
carbohydrate (HC) or high in fat (HF), or were naturally reared on
mother's milk (MF). The HC adult rats were hyperinsulinemic,
normoglycemic, and obese. This study investigates pancreatic islet
insulin release (IR) of the adult first generation (1-) diet
-regulated animals and their second generation (2-) progeny. Male rat
1-HC islets had higher basal IR than either 1-MF or 1-HF control
groups. In addition, glucose (17 mM) failed to increase IR above
basal values in 1-HC islets whereas it stimulated IR in 1-MF and 1-HF
islets. Similar secretory responses were evoked by 2-ketoisocaproic
acid (KIC). Female rat 1-MF and 1-HF islets also had higher glucose
-stimulated IR compared with 1-HC islets. Male rat 2-HC islets had
higher basal IR and reduced sensitivity to glucose and KIC compared
with 2-MF islets, which coincided with hyperinsulinemia.
Glyceraldehyde-3-phosphate dehydrogenase activity in 1-HC and 2-HC
islets was higher than MF islets. These data suggest that basal
insulin release is higher in islets isolated from animals reared as
neonates on a diet high in carbohydrate. Alterations in [beta]-cell
metabolism and secretion probably contribute to the hyperinsulinemia,
reduced glucose sensitivity, and glucose intolerance characteristic
of this rat model.
Received 16 December 1994; accepted in final form 11 May 1995.
APS Manuscript Number E522-4.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.