title: Inhibition of serum oxytocinase activity by prostaglandins.
abstract: The effect of prostaglandins (PGs) and other compounds on human serum oxytocinase (EC 3.4.11.3) activity in vitro was studied by a sensitive assay using S-benzyl-L-cysteine-p-nitroanilide as substrate. PGE1, PGE2 and PGF2 alpha significantly inhibited serum oxytocinase activity in a dose-related manner and in decreasing order of potency. cGMP, 8-bromo-cGMP, indomethacin, polyphloretin phosphate, hypertonic saline and urea were also active. cAMP, db-cAMP, 8-bromo-cAMP, db-cGMP, 5'-AMP, 5'-ADP, 5'-ATP, 5'-GDP, 5'-GTP, aspirin, sodium salicylate, paracetamol, theophylline and IBMX did not inhibit the enzyme activity. The results suggest that the oxytocic action of prostaglandins may be due, at least in part, to an inhibition of oxytocinase activity.
mesh_terms: D000626:Aminopeptidases / Q000037:antagonists & inhibitors*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism; D010122:Cystinyl Aminopeptidase / Q000037:antagonists & inhibitors* / Q000097:blood; D006801:Humans; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D011121:Polyphloretin Phosphate / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology*; D011460:Prostaglandins F / Q000494:pharmacology*; D012462:Saline Solution, Hypertonic; D014508:Urea / Q000494:pharmacology
chemical_list: D011458:Prostaglandins E; D011460:Prostaglandins F; D012462:Saline Solution, Hypertonic; C016276:8-bromocyclic GMP; C004559:S-benzyl-L-cysteine-4'-nitroanilide; D014508:Urea; D011121:Polyphloretin Phosphate; D000626:Aminopeptidases; D010122:Cystinyl Aminopeptidase; D006152:Cyclic GMP; D003545:Cysteine; D007213:Indomethacin