International Journal of Experimental Diabetes Research
Volume 1 (2000), Issue 3, Pages 185-193
doi:10.1155/EDR.2000.185
Correlation Between Pancreatic Islet Uncoupling Protein-2 (UCP2) mRNA Concentration And Insulin Status in Rats
1Laboratoire de Physiopathologie de la Nutrition, CNRS ESA 7059, Université Paris 7-Denis Diderot, Paris, France
2Département de Physlologe, Unversité Laval, Québec, Canada
3CCNRS ESA 5018, Université Paul Sabatier, Toulouse, France
4CEREMOD CNRS UPR 9078, 9, rue Jules Hetzel, Meudon 92190, France
; Accepted 8 March 2000
Copyright © 2000 Nadim Kassis et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Hypothesizing that UCP2 may influence insulin
secretion by modifying the ATP/ADP ratio within
pancreatic islets, we have investigated the expression
of intraislet UCP2 gene in rats showing insulin
oversecretion (non-diabetic Zucker fa/fa obese rats,
glucose-infused Wistar rats) or insulin undersecretion
(fasting and mildly diabetic rats). We found that
in Zucker fa/fa obese rats, hyperinsulinemia
(1222 ± 98 pmol/1 vs. 128 ± 22 pmol/1 in lean Zucker
rats) was accompanied by a significant increase in
UCP2 mRNA levels. In rat submitted to a 5 day
infusion with glucose, hyperinsulinemia (1126 ± 101
pmol/l vs. 215 ± 25 pmol/1 in Wistar control rats),
coincided with an enhanced intraislet UCP2 gene
expression, whereas a 8h or a 2 day-infusion did not
induce significant changes in UCP2 mRNA expression.
In rats made hypoinsulinemic and mildly
diabetic by the injection of a low dose of streptozotocin,
and in 4-day-fasting rats (plasma insulin
28 ± 5 pmol/1) UCP2 gene expression was sharply
decreased. A 3-day-fast was ineffective. The data
show the existence of a time-dependent correlation
between islet mRNA UCP2 and insulin that may be
interpreted as an adaptative response to prolonged
insulin excess.