Enzymological and biochemical changes produced by mercuric chloride in a teleost fish, Channa punctatus

Alterations in the activities of lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in the brian, gills, intestine, kidney, liver and muscles, the levels of glycogen and lactic acid in liver and muscles, and blood glucose have been examined in a fresh-water teleost fish, Channa punctatus after exposure to a sublethal concentration (3 microgram/1) of mercuric chloride for 15, 30 and 60 days. The results revealed that the activities of all the three dehydrogenases were inhibited significantly after 60 days of treatment except for lactate dehydrogenase in brain. Glycogen and lactic acid contents of the liver and muscles and the blood glucose level also decreased significantly after 60 days of exposure. Though gills and muscles showed weak activity of the three dehydrogenases, the percentage of inhibition was more marked in these tissues than in others.