Impact of γ-hexachlorocyclohexane on the in vitro production of steroids from endogenous and exogenous precursors in the spermiating roach, Rutilus rutilus

Abstract

Testicular fragments from spermiating roach were incubated with 0, 1, 10 and 20 mg/L of γ-hexachlorocyclohexane (γ-HCH), and either carp hypophyseal homogenate (chh) or 3H-17-hydroxyprogesterone ( 3H-17P). The endogenous production of testosterone (T), 17-hydroxyprogesterone (17P), 17,20β-dihydroxy-4-pregnen-3-one (17,20βP), 11-ketotestosterone (KT), testosterone glucuronide (TG), and 17,20β-dihydroxy-4-pregnen-3-one glucuronide (17,20βPG) was measured by radioimmunoassay. The effect of γ-HCH on the testicular metabolism of 3H-17P was examined by thin layer and high performance liquid chromatography. Endogenous production of T was stimulated by 1 mg/L γ-HCH but inhibited at higher doses, while its glucuronide was higher in all incubations containing γ-HCH compared with controls. 17P and KT production was lower at all concentrations of γ-HCH compared with controls, but the low endogenous 17,20βP production was unaffected. γ-HCH had a much lower impact on the metabolism of exogenous 17P than on endogenous precursors. The major metabolite of 17P in the testis, 17,20βP, showed a significant increase in yield in response to γ-HCH together with a decrease in production of its glucuronide. There was also a significant increase in yield of testosterone at some concentrations, but none of the other metabolites were affected by γ-HCH exposure. The results show that the balance of steroid production by testes of spermiating roach is significantly perturbed by γ-HCH and suggests that the pesticide affects predominantly the stages of steroidogenesis leading to 17-hydroxyprogesterone production.