In vitro effects of toxaphene on mitochondrial calcium ATPase and calcium uptake in selected rat tissues.
In vitro effects of toxaphene on Ca2+-ATPase activity and 45Ca2+-uptake were studied in mitochondrial fractions of heart, kidney and liver tissues of rat. Mitochondrial fractions were prepared by the conventional centrifugation method. Ca2+-ATPase activity was determined by measuring the inorganic phosphate liberated during ATP hydrolysis. Toxaphene inhibited Ca2+-ATPase in a concentration dependent manner in all the three tissues. Substrate activation kinetics, with heart, kidney and liver tissue fractions, revealed that toxaphene inhibited Ca2+-ATPase activity non-competitively by decreasing the maximum velocity of the enzyme without affecting the enzyme-substrate affinity. Toxaphene also inhibited mitochondrial 45Ca2+-uptake in the three selected tissues in a concentration dependent manner. These results indicate that toxaphene is an inhibitor of mitochondrial Ca2+-ATPase and calcium transport in heart, kidney and liver tissues of rat.
Trottman
C H
CH
Prasada Rao
K S
KS
Morrow
W
W
Uzodinma
J E
JE
Desaiah
D
D
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D007306:Insecticides / Q000494:pharmacology*; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008297:Male; D008928:Mitochondria / Q000201:enzymology*; D008929:Mitochondria, Heart / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D010710:Phosphates / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014112:Toxaphene / Q000494:pharmacology*
D007306:Insecticides; D010710:Phosphates; D014112:Toxaphene; D000252:Calcium-Transporting ATPases; D002118:Calcium