AJP - Endocrinology and Metabolism, Vol 254, Issue 6 E756-E759, Copyright © 1988 by American Physiological Society
Modulatory effect of glucose on VIP-induced gastric somatostatin release
R. Schmid, V. Schusdziarra and M. Classen
Department of Internal Medicine II, Technical University of Munich, Federal Republic of Germany.
The present study was designed to examine the effect of increasing
perfusate glucose concentrations on vasoactive intestinal peptide
(VIP)-induced somatostatin (SLI) release from the isolated rat stomach. The
stomach of overnight-fasted rats was perfused with Krebs-Ringer buffer
containing 100, 150, or 200 mg/dl glucose, respectively. VIP was
administered at 10(-12), 10(-11), 10(-9), and 10(-8) M. At a normal glucose
concentration of 100 mg/dl, VIP at doses of 10(-12), 10(-11), and 10(-9) M
elicited a small inhibitory effect on SLI release by 200-300 pg/min (P less
than 0.01). As reported previously at 10(-8) M, VIP stimulated gastric SLI
secretion by 500 pg/min (P less than 0.01). Increasing perfusate glucose to
150 mg/dl resulted in a stimulation of SLI release by all four
concentrations of VIP with a maximal effect at 10(-9) M. During 200 mg/dl
glucose, VIP had no effect in concentrations below 10(-9) M, and only the
two highest doses (10(-9) and 10(-8) M) stimulated SLI release
significantly. In the absence of VIP, glucose had no effect on gastric SLI
release. In conclusion, the present data demonstrate for the first time
that at normal glucose levels VIP has not only stimulatory but also
inhibitory effects on gastric SLI, and second, a modest elevation of
glucose has a modulatory effect on gastric D-cell function.
