Gonadotoxic effects of 2-hexanone and 1,2-dibromo-3-chloropropane on the enzymatic activity of rat testicular 17 alpha-hydroxylase/C17,20-lyase.

In this study the gonadotoxic effects of 2-hexanone administered as a pretreatment and/or 1,2-dibromo-3-chloropropane administered as a challenge on the activity of several key steroidogenic enzymes in the rat testis were examined. Despite the absence of an effect when either treatment was administered individually, the pretreatment/challenge combination inhibited the steroidogenic capacity of the rat testis. The specific activity of testicular 17 alpha-hydroxylase was significantly reduced (P less than 0.05), with respect to the control, following the pretreatment/challenge combination. There were no significant differences between the control and the individual treatments. The inhibition of 17 alpha-hydroxylase activity occurred in the absence of significant differences in testis weight and testicular protein content. This inhibition of testicular steroidogenic enzyme activity was specific as the activity of another testicular enzyme, namely C17,20-lyase, was not affected by any treatment. The decline in rat testicular 17 alpha-hydroxylase activity 18 h after the 1,2-dibromo-3-chloropropane challenge precedes the reported alterations in the seminiferous epithelium following this same treatment. The results of the present study indicate that the steroidogenic cell of the testis, i.e. the Leydig cell, is a potential site for the primary toxic effects of these agents in the rat testis.