Nandrolone decanoate-induced hypogonadism in male rats: Dose- and time-dependent effects on pituitary and testicular hormonal functions.

Anabolic-androgenic steroids (AASs) impairment of reproduction has been reported. We investigated dose- and time-dependent effects of Nandrolone decanoate (ND) on reproductive system in comparison with Testosterone enanthate (TE). Male Wistar rats were administrated with 1, 3, and 9 mg/kg/weeks ND or 1 and 3 mg/kg/weeks TE for 8 weeks, and testicular phenotype and reproductive hormones were assessed at 4 and 8 weeks post-treatments. AASs × treatment period interaction was significant for gonadosomatic index (GSI), testosterone (T), 17β-estradiol (E₂), and luteinizing hormone (LH). At 4 weeks post-treatment, GSI was decreased in rats treated with 3 mg/kg/weeks ND and T was decreased in all ND-treated groups, while no significant changes in LH levels were observed. At 8 weeks post-treatment, GSI was decreased in rats treated with 1 and 3 mg/kg/weeks ND and with 3 mg/kg/weeks TE, T was decreased in all groups, and E₂ and LH were increased and decreased, respectively, in rats treated with 9 mg/kg/weeks ND and with 3 mg/kg/weeks TE. The testes showed histopathological defects in both ND- and TE-treated rats suggesting a delay in seminiferous cycle. This study shows AASs-induced hypogonadism at low-dose that coincided with inhibition of T biosynthesis and disruption of T feedback on pituitary.