Testosterone Effect on Insulin Content, Messenger Ribonucleic Acid Levels, Promoter Activity, and Secretion in the Rat1
Coexistence of hyperinsulinemia and hyperandrogenism in women has been frequently described. Most of the studies addressing this issue have focused on the mechanisms by which insulin produces hyperandrogenism. In the present study, we analyzed the effects of testosterone in vivo and in vitro upon in...
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Published in | Endocrinology (Philadelphia) Vol. 142; no. 4; pp. 1442 - 1447 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Endocrine Society
01.04.2001
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Online Access | Get full text |
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Summary: | Coexistence of hyperinsulinemia and hyperandrogenism in women has been
frequently described. Most of the studies addressing this issue have
focused on the mechanisms by which insulin produces hyperandrogenism.
In the present study, we analyzed the effects of testosterone in
vivo and in vitro upon insulin gene expression
and release in the rat. Our studies demonstrate that testosterone
increases insulin messenger RNA (mRNA) levels in vitro
as well as in vivo. In both prepuberal and intact adult
rats, serum testosterone concentrations were positively correlated with
insulin mRNA levels and insulin concentration in serum. Testosterone
deprivation after gonadectomy decreased both insulin gene expression
and serum insulin concentration. Insulin mRNA levels were partially
restored after 3 days of testosterone administration and serum insulin
was 80% and 27% above baseline values at 5 and 7 days posttreatment.
Primary cultured pancreatic islets treated with the sexual steroid
increased about 80% insulin mRNA, as well as protein, and release. In
transfected islets, testosterone increased the activity of the −410 bp
rat insulin promoter I by 154%. These data demonstrate that
testosterone has a direct effect upon pancreatic islet function by
favoring insulin gene expression and release. |
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ISSN: | 0013-7227 1945-7170 |
DOI: | 10.1210/endo.142.4.8069 |