Impact of malathion and gamma-BHC on lipid metabolism in the freshwater female catfish, Heteropneustes fossilis.

Female Heteropneustes fossilis were exposed to sublethal concentrations of malathion (5 and 20 microliters liter-1) and gamma-BHC (4 and 16 micrograms liter-1) for 4 weeks during different phases of their annual reproductive cycle. The impact of these pesticides on free fatty acids (FFA), monoglycerides (MG), diglycerides (DG), triglycerides (TG), phospholipids (PL), free cholesterol (CF), and esterified cholesterol (CE) in the liver, plasma, and ovary was assessed. During the preparatory phase both the pesticides reduced the levels of all the hepatic and ovarian lipids with elevated hepatic CE. During the prespawning phase these pesticides decreased all the lipids in the liver, plasma, and ovary with the elevation of hepatic FFA and CE. During the spawning phase a reduction of hepatic MG and CF with a decreased level of plasma and ovarian levels of FFA and PL was recorded, whereas ovarian levels of TG and CE were elevated in response to both the pesticides. During postspawning and resting phases all the hepatic lipids were reduced with the elevation of CE in response to the exposure. These pesticides also restricted their mobilization to the ovary. Cholesterol biosynthesis seemed unaffected but the hydrolysis of CE to CF was adversely affected during preparatory and prespawning phases which is a period of sex steroid hormone biosynthesis.