Ra. Silvestre et al., Effect of leptin on insulin, glugacon and somatostatin secretion in the perfused rat pancreas, HORMONE MET, 33(4), 2001, pp. 207-212
We have investigated the effect of rat leptin as well as the 22-56 fragment
of this molecule on pancreatic hormone secretion in the perfused rat pancr
eas. In pancreases from fed rats, leptin failed to alter the insulin secret
ion elicited by glucose, arginine or tolbutamide, but inhibited the insulin
response to both CCK-8 and carbachol, secretagogues known to act on the B-
cell by increasing phospholipid turnover. This insulinostatic effect was al
so observed with the 22-56 leptin fragment, In pancreases obtained from 24-
hour fasted rats, no effect of leptin on carbachol-induced insulin output w
as found, perhaps as a consequence of depressed B-cell phospholipid metabol
ism. Leptin did not influence glucagon or somatostatin release. Our results
do not support the concept of leptin as a major regulator of B-cell functi
on. Leptin inhibition of carbachol-induced insulin output might reflect a r
estraining effect of this peptide on the cholinergic stimulation of insulin
release.