gamma-BHC- and cythion-induced alterations in lipid metabolism in a freshwater catfish, Clarias batrachus, during different phases of its annual reproductive cycle.

Specimens of either sex of the freshwater catfish Clarias batrachus were exposed to safe and sublethal concentrations of gamma-BHC (2 and 8 ppm) and Cythion (1 and 4 ppm) for 4 weeks during different phases of the annual reproductive cycle. Their effects on various lipid fractions, viz., triglycerides (TG), phospholipids, free cholesterol, and esterified cholesterol, were studied in liver, plasma, gonads, and muscle. These pesticides suppressed the level of hepatic TG in females during the preparatory, prespawning, and postspawning phases, while during the spawning phase they stimulated an increase in its level. However, in males, these pesticides were ineffective in having any effect on liver TG during the spawning and postspawning phases, but in the preparatory phase, as with the female, they increased its levels, while in the prespawning phase they decreased liver TG levels. Hepatic phospholipid biosynthesis was impaired by gamma-BHC but Cythion had no effect on it. Cholesterol biosynthesis as such appeared to be unaffected by these pesticides but the dynamics of free and esterified cholesterol levels were disturbed in response to Cythion and gamma-BHC. These pesticides greatly reduced the mobilization of these hepatic lipids to gonads. Muscle lipids were least affected by these pesticides.