Effect of chlorpromazine and gossypol on Ca (2+) -ATPase activity in the microsomal membranes of rat testes
Mazumder, B.; Sikdar, R.; Sen, P.C.
Indian Journal of Biochemistry and Biophysics 28(2): 136-139
1991
ISSN/ISBN: 0301-1208 PMID: 1831790 Document Number: 381135
The microsomal membranes isolated from rat testes have been found to contain a Mg(2+)-dependent and a Mg(2+)-independent Ca(2+)-ATPase. The enzyme activities were inhibited by two contraceptive drugs--gossypol and chlorpromazine. The inhibition by the former was affected by the presence of ligand(s) and not the substrate in the incubation medium, whereas ligand(s)/substrate did not affect the inhibition by chlorpromazine. This may be explained from the fact that the binding of chlorpromazine and ligand(s)/substrate to the enzyme are independent of each other whereas in case of gossypol the ligand(s) compete with the drug at the binding site of the enzyme.