Testosterone rapidly stimulates insulin release from isolated pancreatic islets through a non-genomic dependent mechanism

The action of testosterone on the Ca-45(2+) uptake and insulin secretion was studied in short-term experiments using isolated pancreatic islets of Langerhans. Testosterone (1 mu M) stimulated Ca-45(2+) uptake within 60 seconds of incubation on similar proportion than tolbutamide. Also, the hormone rapidly increased insulin release (34%; 180 seconds) on the presence of non-stimulatory concentrations of glucose (3 mM). Impermeant testosterone-BSA significantly stimulated the secretion of insulin to a lower percentage (10%). The action of the hormone is specific - neither 17 beta-E2 nor progesterone stimulated insulin secretion in the presence of 3 mM glucose. The action of testosterone on insulin secretion was dose-dependent, and at rat plasma physiological concentrations (25 nM), stimulus was 17 % (p < 0.05). In conclusion, in isolated pancreatic islets experiments, physiological concentration of testosterone rapidly stimulate insulin secretion and Ca-45(2+) uptake through a membrane bound mechanism.