Testosterone rapidly stimulates insulin release from isolated pancreatic islets through a non-genomic dependent mechanism.
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 microM) 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 17beta-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.
Grillo
M L
ML
Departamento de Fisiologia, ICBS, UFRGS, Porto Alegre, Brazil.
Jacobus
A P
AP
Scalco
R
R
Amaral
F
F
Rodrigues
D O
DO
Loss
E S
ES
Wassermann
G F
GF
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000494:pharmacology*
D007328:Insulin; D013739:Testosterone; D002118:Calcium