Exogenous testosterone, finasteride and castration effects on testosterone, insulin, zinc and chromium in adult male rats

Background: Although effects of trace elements on secretion of sex steroids and insulin have been studied, the effects of these hormones on serum level of trace elements have been rarely investigated. The aim of the present study was to evaluate the effect of testosterone and finasteride administration and castration on serum levels of testosterone, insulin, zinc and chromium. Methods: Male adult rats (n = 32) were divided into 4 groups (n = 8). Group 1, control; Group 2, castration, castration was done at the first day of the study; Group 3, finasteride (20 mg/kg/day, dissolved in drinking water) and Group 4, testosterone (5 mg/kg/day, i.p.). At the end of the period of the study (35 days), serum testosterone, insulin, zinc and chromium levels were determined in the blood samples collected directly from the right atrium of the heart of the animals. Results: The data indicated that the serum levels of testosterone, insulin and zinc were significantly increased (P 0.01) in testosterone-administrated and finasteride groups, but the level of chromium was decreased in both groups (P 0.01). Castrated group had the lowest serum levels of testosterone, insulin and zinc (P 0.05). Also, the levels of serum chromium in this group were increased. Conclusion: The study demonstrates that testosterone and finasteride increases insulin and zinc levels and decreases chromium levels in the serum of male adult rats. According to these data, it seems that testosterone may affect glucose cycle through effect on serum insulin levels and trace elements such as zinc and chromium.