K.V. Sastry

Effect of cadmium on some aspects of carbohydrate metabolism in a freshwater catfish Heteropneustes fossilis

The chronic toxic effects of cadmium (0.26 mg/l) on the carbohydrate metabolism of a teleost fish, Heteropneustes fossilis were examined after 15, 30 and 60 days of exposure. The alterations produced after 15 and 30 days of exposure were similar in nature but were different in fish treated for 60 days. Fish were hyperglycemic and hyperlactacidemic after 15 and 30 days of exposure. The liver and muscle glycogen content was depleted in the first two periods of exposure. In contrast, 60 days of cadmium treatment increased the glycogen content of the two tissues. Liver lactic acid level was elevated after 15 days. Muscle lactic acid content fell significantly after 15 and 60 days of exposure, but it was elevated after 30 days. In general, the activities of lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase increased in liver, kidney, intestine, ovary, gills and muscles of fish exposed to cadmium for 15 and 30 days. The increase in activities of the three dehydrogenases continued up to 60 days in intestine and ovary. In gills succinate dehydrogenase activity was elevated after 60 days also, but pyruvate dehydrogenase was inhibited. The activities of the three dehydrogenases decreased in liver, kidney and muscles.

Enzymological and biochemical changes produced by chronic chromium exposure in a teleost fish, Channa punctatus

The chronic toxic effects of chromium (2.6 mg/1) on the carbohydrate metabolism of a teleost fish, Channa punctatus were examined after 60 and 120 days of exposure. After 60 days the lactic acid content of blood and muscles was increased but liver lactic acid content decreased. Liver glycogen was also depleted. The activity of lactate dehydrogenase was inhibited in liver and kidney. Pyruvate dehydrogenase and succinate dehydrogenase activities were also inhibited in all the tissues except muscles. Fish were hypoglycemic and hyperlactemic after 120 days of exposure to chromium. The glycogen content increased in liver but decreased in muscles. Lactate dehydrogenase activity was inhibited in all the six tissues. The activity of pyruvate dehydrogenase decreased in liver, intestine, gill and muscles. In muscles succinate dehydrogenase activity was elevated but inhibition was recorded in other tissues.

Chronic toxic effects of the carbamate pesticide sevin on carbohydrate metabolism in a freshwater snakehead fish, Channa punctatus

The effect of exposure to a sublethal concentration of the carbamate pesticide, sevin (1.05 mg/l), on biochemical parameters of blood, liver and muscle, and enzyme activities in liver, kidney, intestine, brain, gills, and muscles of the freshwater teleost fish, Channa punctatus, was studied after 15, 30 and 60 days. The alterations produced were more marked after 30 and 60 days of exposure than after 15 days; fish were hyperglycaemic and hyperlactacidemic. Glycogen content of liver and muscles decreased, but lactic acid levels of the two tissues increased. In liver, muscles, brain and gills the lactate dehydrogenase (LDH) activity was higher in pesticide-exposed fish in comparison to control fish, but the same enzyme activity was inhibited in kidney and intestine. Decreased pyruvate dehydrogenase (PDH) activity occurred in all six tissues. Succinate dehydrogenase (SDH) activity decreased in muscle at the three time periods and after 30 and 60 days in liver and brain. However, in kidney and intestine the latter enzyme activity was elevated. The results suggest that anaerobic metabolism was favoured and aerobic oxidation of pyruvate was impaired in fish exposed to sevin.

In vivo effects of cadmium on some enzyme activities in tissues of the freshwater catfish, Heteropneustes fossilis.

Alterations in the activities of some enzymes in a freshwater catfish, Heteropneustes fossilis, have been examined in liver, kidney, intestine, ovary, gills, and muscles after exposure to 0.26 mg/liter of cadmium for 15, 30, and 60 days. The fish were hyperglycemic and hyperlactemic after 15 and 30 days of exposure. The liver and muscle glycogen content was depleted in the first two periods of exposure. In contrast, 60 days of cadmium treatment increased the glycogen content of the two tissues. Liver lactic acid level was elevated after 15 days. Muscle lactic acid content fell significantly after 15 and 60 days of exposure, but it was elevated after 30 days. Acid phosphatase activity was inhibited in liver, ovary, and gills but the enzyme activity increased in kidney and intestine. The activity of alkaline phosphatase decreased in liver, kidney, and intestine but elevation was recorded in ovary and muscles. In all three exposure periods, hexokinase activity of kidney and ovary was inhibited but the enzyme activity increased in intestine. Hexokinase showed elevation in liver, gills, and muscle after 15 and 30 days of exposure and inhibition after 60 days of exposure. The activity of xanthine oxidase decreased in liver and muscles and elevated in the rest of the tissues. Glutamate dehydrogenase fell significantly in intestine, ovary, and gills. In liver, kidney, and muscles the enzyme activity was elevated. Liver, intestine, gills, and muscles showed elevation in aminoacid oxidase activity. However, the enzyme activity was inhibited in kidney and in ovary.

Effect of endosulfan and quinalphos on intestinal absorption of glucose in the freshwater murrel, Channa punctatus

The effect of four concentrations of two agricultural pesticides, endosulfan and quinalphos (100 ppm, 10 ppm, 1 ppm, 0.1 ppm) on the rate of uptake of glucose by the intestine of a teleost fish, Channa punctatus after 1 h at 23 degrees C has been studied. The rate of absorption of glucose by the intestine was also examined in fish exposed to LC50 for 96 h (endosulfan 2 micrograms/l, quinalphos 0.25 mg/l) and to a sublethal concentration of the two pesticides for 15 and 30 days by bath. All the four concentrations of the two pesticides decreased the rate of intestinal glucose transport. Increase in the concentration of the pesticides decreased the uptake of glucose to a greater extent but the decrease was not proportional to the increase in the concentration of the pesticides. The rate of glucose absorption was also reduced by exposure of fish to the pesticides by bath. The decrease in intestinal glucose transport was greater in fish exposed for 96 h than after either 15 or 30 days. Of the two pesticides, endosulfan was more effective in reducing the glucose transport rate.

Toxic effects of chromium in a freshwater teleost fish, Channa punctatus

The effect of in vivo exposure to a sublethal concentration of hexavalent chromium for 30 days on blood glucose, blood liver and muscle lactic acid; haemoglobin, liver and muscle glycogen; and activities of lactate dehydrogenase (LDH), pyruvate dehydrogenase (PHD) and succinate dehydrogenase (SDH) in liver, muscle, kidney, gills and brain has been studied. Blood glucose and lactic acid levels were elevated. Liver glycogen was depleted but muscle glycogen content increase. The activities of LDH and SDH in liver were elevate. Elevation was also observed in muscle LDH and PDH activities, showing that the rate of glycolysis is increased. No change was noted in haemoglobin content of blood or in the activities of the three dehydrogenases in kidney and gills.

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.

Effect of cadmium and chromium on the intestinal absorption of glucose in the snakehead fish, Channa punctatus

The effect of five concentrations of cadmium and chromium (10 mM, 1 mM, 0.1 mM, 0.01 mM and 0.001 mM) on the rate of absorption of glucose from the intestine of te snakehead fish, channa punctatus, was studied at 23 degrees C. All concentrations of cadmium decreased the rate of glucose transport. Maximum decrease was recorded with 10 mM of cadmium. The rate of transport decreased with an increase in the concentration of cadmium used. Chromium increased glucose absorption rate at all concentrations examined; the highest rate of absorption occurred at 0.001 mM of chromium.

Acute and chronic effects of diazinon on the activities of three dehydrogenases in the digestive system of a freshwater teleost fish Channa punctatus

The effect of acute exposure to LC50 for 96 h (3.1 mg/l) and chronic exposure to a sublethal concentration (0.31 mg/l) of diazinon has been studied in the liver, stomach, intestine and pyloric ceca of a freshwater teleost fish, Channa punctatus. In acute exposure succinate dehydrogenase (SDH) activity was elevated in intestine and pyloric ceca. No alteration was noted in lactate dehydrogenase activity but pyruvate dehydrogenase was inhibited in pyloric ceca. Chronic exposure resulted in inhibition of the activities of the three dehydrogenases in all the four parts at both intervals.

Alteration in some biochemical and enzymological parameters in the snake head fish channa punctatus exposed chronically to quinalphos

Abstract The effect of chronic quinalphos exposure (0.025 mg/1) for 15 and 30 days on the levels of glucose, lactic acid and haemoglobin in the blood; glycogen and lactic acid contents of the liver and muscles; and the activities of hexokinase, lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in liver, kidney, intestine, brain, gills and muscles was examined. Blood glucose, lactic acid and haemoglobin levels decreased in quinalphos exposed fish. Glycogen content of liver and muscles increased but lactic acid decreased. Hexokinase was inhibited in intestine and muscles after 30 days of exposure but increase in enzyme activity was noted in gills. Lactate dehydrogenase activity was inhibited in all the six tissues. Pyruvate dehydrogenase activity of liver, kidney, gills and muscles was inhibited. However, in brain the enzyme activity was elevated. Succinate dehydrogenase activity was elevated in intestine and inhibited in other tissues.