Testosterone Rapidly Stimulates Insulin Release from Isolated Pancreatic Islets through a Non-genomic Dependent Mechanism

Abstract

The action of testosterone on the ⁴⁵Ca²⁺ uptake and insulin secretion was studied in short-term experiments using isolated pancreatic islets of Langerhans. Testosterone (1 µM) stimulated ⁴⁵Ca²⁺ 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 17β-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 ⁴⁵Ca²⁺ uptake through a membrane bound mechanism.

Key words

Testosterone - insulin release - pancreatic islets - ⁴⁵Ca²⁺ uptake

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