Here we evaluated the effect of leptin on glucose induced insulin secretion by normal rat pancreatic islets. We show in perifusion experiments that leptin had no acute effect on the secretory activity of β-cells. However, following preexposure to leptin a pronounced time- and dose-dependent inhibition of both first and second phases of secretion was observed. Maximum inhibition was obtained at 24 h and with 100 nM leptin. This inhibition did not involve a decrease in cellular insulin content. It was also not observed with islets from fa/fa rats. Leptin thus inhibits insulin secretion by a mechanism which requires long-term preexposure to the hormone and which may involve alteration in β-cell gene expression.
Roduit, R., & Thorens, B. (1997). Inhibition of glucose-induced insulin secretion by long-term preexposure of pancreatic islets to leptin. FEBS Letters, 415(2), 179–182. https://doi.org/10.1016/S0014-5793(97)01115-0