Immunohistomorphometric changes of the pituitary gonadotropic cells after testosterone application in a rat model of the andropause

摘要

Andropause, the culminating phase of male ageing, is characterized by deregulation of the hypothalamic-pituitarygonadalaxis and low circulating free testosterone. The aim of this study was to investigate the immunohistomorphometriccharacteristics of the pituitary gonadotropic i.e. follicle-stimulating hormone (FSH) and the luteinizing hormone (LH)producing cells after testosterone application in a rat model of the andropause. Middle-aged Wistar rats were divided intoorchidectomized (ORX; n=8) and testosterone treated orchidectomized (ORX+T; n=8) groups. Testosterone propionate (5mg/kg b.m. /day) was administered for three weeks, while the ORX group received the vehicle alone. Immunohistochemicallystained FSH and LH cells underwent morphometric and optical density-related analysis, while circulating concentrationsof the sex steroids were measured by immunoassays. Serum concentrations of testosterone and estradiol were significantly(p0.05) increased by 24 and 2.7 fold respectively, compared to the ORX group. The volume of FSH and LH cells wassignificantly (p0.05) decreased by 51.3% and 56.6% respectively, in comparison with ORX rats. Relative volume densityof FSH and LH cells was also significantly (p0.05) decreased by 54.0% and 72.8% respectively, compared to the ORXgroup. Results related to the optical density of gonadotropic cells (reflecting their hormonal content) were in line withthe morphometric findings i.e. this parameter of FSH and LH cells was significantly (p0.05) decreased by 25.7% and16.2% respectively, in comparison with ORX rats. Conclusion: In conclusion, applied testosterone increased the serumconcentrations of sex steroids, as well as it decreased morphometric parameters and optical density of gonadotropic cells inORX rats.