Reproductive endocrine disruption in the freshwater catfish, Heteropneustes fossilis, in response to the pesticide γ-hexachlorocyclohexane

Abstract

Both male and female freshwater catfish, Heteropneustes fossilis, were exposed to safe (SC; 0.1 and 1.0 mg/L) and sublethal (SL; 10 mg/L) concentrations of an agricultural pesticide, γ-hexachlorocyclohexane ( γ-HCH) for 4 weeks during the active pre-spawning (vitellogenic) phase of their annual reproductive cycle. On the last day of exposure, 18 h before killing, fish were treated intramuscularly (i.m.) with [I- 14C]acetic acid (74 kBq per fish). After 4 weeks of exposure, we monitored the effects of γ-HCH on gonadosomatic index (GSI); on plasma concentrations of gonadotropin (GtH), testostosterone (T), 11-ketotestosterone (11-KT), 17 β-estradiol (E 2); and on hepatic incorporation of [I- 14C]acetic acid into total phospholipids (TP) and the fractions thereof: phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI), and phosphatidylethanolamine (PE). In both the sexes, GSI and plasma GtH were decreased significantly in response to γ-HCH exposure. Plasma T and 11-KT in males, and plasma T and E 2 in females declined significantly in response to γ-HCH exposure. In both the sexes, hepatic incorporation of [I- 14C]acetic acid into PS and PI increased significantly, whereas incorporation into TP, PC, and PE was significantly reduced after γ-HCH exposure. Our findings demonstrated that γ-HCH exposure depressed GSI, plasma GtH, sex steroids, and [I- 14C]acetic acid incorporation into hepatic TP, and had very selective and specific effects on various classes of TP, resulting either from the hypothalamo-hypophyseal-gonadal axis or from direct action on hepatic and steroidogenic enzymes during the pre-spawning phase, causing reproductive endocrine disruptions.