Effect of prostaglandins on rat heart sarcolemmal ATPases.
The ability of prostaglandins (PG) D2, E1, E2, F2 alpha and I2 (2.8 X 10(-11) to (2.8 X 10(-7) M) to modify Ca2+, Mg2+ and (Na+ + K+)-ATPase activities of rat heart sarcolemmal membrane fractions was examined. Administration of PGE2, PGF2 alpha, and PGI2 reduced basal (Na + + K+)-ATPase activity by up to 30, 80, and 80%, respectively. PGE1 and PGD2 were ineffective at any concentration. Neither Mg2+ -ATPase nor Ca2+ -ATPase was affected by PG treatment. Kinetic analysis revealed that the (Na+ + K+)-ATPase activity reducing ability of PGE2, PGF2 alpha and PGI2 was of a complex nature involving a reduction in Vmax and an elevation of the respective K values for either substrate or activator. These results demonstrate that some PG's are potent inhibitors of rat heart (Na+ + K+)-ATPase. These PG's produced varied inotropic influences on isolated heart preparations and it is uncertain whether their myocardial actions are dependent on enzyme inhibition.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D011453:Prostaglandins / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012508:Sarcolemma / Q000201:enzymology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D011453:Prostaglandins; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase