In VitroEffects of γ-Hexachlorocyclohexane onin VitroBiosynthesis and Metabolism of Steroids in GoldfishCarassius auratus

Abstract

Testicular and ovarian fragments ofCarassius auratus,taken during the reproductively active prespawning phase (June) of its annual reproductive cycle, were incubated with different concentrations (0 mg/ml, 0 ppm; 0.001 mg/ml, 1 ppm; 0.01 mg/ml, 10 ppm; and 0.02 mg/ml, 20 ppm) of γ-hexachlorocyclohexane (γ-HCH) in the presence of either exogenous precursor [3H]-17-hydroxyprogesterone ([3H]17-P) or carp hypophyseal homogenate. The free (unconjugated) and conjugated metabolites (glucuronides and sulfates) of [3H]-17-P [androstenedione (AD), androstenetrione, 17-hydroxyprogesterone, 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 thein vitrometabolism of [3H]-17-P, in males, free steroids of AD, T, 17,20αP, 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-HCHin vitroperturbed the steroid biosynthesis during this phase thereby affecting reproductive physiology.