Histological parameters of the adrenal cortex after testosterone application in a rat model of the andropause

Histological analysis of the adrenal cortex, after testosterone application in a rat model of the andropause, was the main subject of the present study. Middle-aged Wistar rats were divided into sham-operated (SO; n=8), orchidectomized (Orx; n=8) and testosterone treated orchidectomized (Orx+T; n=8) groups. Testosterone propionate (5 mg/kg b.w. /day) was administered for three weeks, while SO and Orx groups received the vehicle alone. Histological objectives were achieved using stereology, histochemistry and steroid receptor immunostaining. The concentrations of testosterone, aldosterone, corticosterone and DHEA were determined by immunoassays. Expectedly, increased (p<0.05) serum concentration of testosterone was observed in Orx+T group. The volume of ZG cells and nuclei increased in Orx+T animals by 50% and 25% (p<0.05) respectively, but the serum concentrations of aldosterone decreased (p<0.05) by 60%, all compared to the same parameters in Orx group. The immunostaining for androgen receptors (ARs) suggested their cytoplasmic localization in ZG cells of Orx+T rats. Volume of the ZF cell nuclei in Orx+T group decreased (p<0.05) by 17%, which was followed by the significant (p<0.05) fall in corticosterone production and secretion, all in comparison with Orx animals. Also, nuclear immunolocalization of ARs of high optical density was observed through the ZF of Orx+T group. In Orx+T rats volume of ZR cells and nuclei, and circulating DHEA concentration increased (p<0.05) by 68%, 22% and about 6.6 times respectively, compared to Orx animals. Besides the extra-receptor actions in adrenal cortex, testosterone supposedly affects some steroidogenesis-related gene expression, as indicated by centripetal rise in the number of nuclear ARs.