In Vitro Effects of γ-Hexachlorocyclohexane on Biosynthesis and Metabolism of Steroids in Goldflsh Carassius auratus (L.)

Abstract

Testicular and ovarian fragments of Carassius auratus , taken during the reproductively active prespawning phase (June) of its annual reproductive cycle, were incubated with different concentrations (0 mg/ml,0.001 mg/ml, lppm;0.01 mg/ml, 10ppm; and 0.02 mg/ml, 20 ppm) of γ-hexachlorocyclohexane (γ-HCH) in the presence of either exogenous precursor [ 3 H]-17-hydroxyprogesterone ([ 3 H]-17-P 96.5kBq, 13.04ng/Incubation) or carp hypophyseal homogenate (chh, 100 μγg/incubation). The free (unconjugated) and conjugated metabolites (glucuronides and sulfates) of [ 3 H]-17-P [androstenedione (AD), androstenetrione, 17-hydroxyprogeste-rone, testosterone (T), 11- deoxycortisol (S), 17, 20α-dihydroxy-4-pregnen-3-one (17,20αP), 17,20β-dihydroxy-4-pregnen-3-one (17, 20βP), 7α-pregnanetetrols (7α-P), and other polar metabolites] were separated by thin layer chromatography and high performance liquid chromatography. The endogenous production of unconjugated (free) steroids T, 17,20βP, S and 11-ketotestosterone (11-KT) in response to γ-HCH were measured by radioimmunoassay. Among the in vitro metabolism of [ 3 ]-17-P, in males; free steroids of AD, T, 17,20aP, S and polar free steroids were increased with the decreased yield of 11-KT. Percentage yield of testosterone glucuronide (TG) was increased with highly significant decreased yields of polar glucuronide steroids. The sulfate steroids of 17, 20αP, 17, 20βP, S and 11-KT remain unchanged. In females, the decreased percentage of yield of AD and S, and elevated T were noticed. The yield of TG was increased with decreased yield of 7α-P glucuronides. The percentage yield of AD sulfate and sulfate steroids of 17, 20αP, 17, 20βP and S were noted to be increased, but the yield for S sulfate was very high. Endogenous production of T was increased in both sexes in the presence of γ-HCH, but 11-KT in male and S in female were depressed. 17,20βP was stimulated at some concentrations in both sexes but levels were very low. Results indicate that γ-HCH in vitro perturbed the steroids biosynthesis during this phase thereby affecting reproductive physiology.