title: Angiotensin converting enzyme inhibitory activity of SCH 33844 (spirapril) in rats, dogs and monkeys.
abstract: SCH 33844 is a new non-sulfhydryl-containing angiotensin converting enzyme (ACE) inhibitor. SCH 33844 diacid inhibited hydrolysis of the synthetic substrate hippuryl-histidyl-leucine by rabbit lung ACE in vitro with an IC50 (concentration inhibiting enzyme by 50%) of 0.81 nM. The ester was 83 times less active. Intravenous administration of SCH 33844 and its diacid inhibited pressor responses to angiotensin I (AI) in anesthetized rats with calculated ID50's of 16 and 8 micrograms/kg, respectively. Oral administration of SCH 33844 (0.03-1 mg/kg) inhibited AI pressor responses in conscious rats with a duration of 24 hr at the highest dose. The diacid was inactive. Intravenous administration of SCH 33844 (100-1000 micrograms/kg) or its diacid (30 micrograms/kg) to anesthetized dogs inhibited AI pressor activity and potentiated the depressor response to bradykinin. SCH 33844 inhibited AI responses in conscious dogs following oral administration of 0.3-3 mg/kg. Oral administration of SCH 33844 (1 mg/kg) to conscious monkeys inhibited AI pressor responses for the 4 hr duration of study. In conclusion, SCH 33844 is a potent, orally effective ACE inhibitor in rats, dogs and monkeys.
mesh_terms: D000803:Angiotensin I / Q000037:antagonists & inhibitors; D000806:Angiotensin-Converting Enzyme Inhibitors; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D055598:Chemical Phenomena; D002621:Chemistry; D004285:Dogs; D004333:Drug Administration Routes; D004357:Drug Synergism; D004656:Enalapril / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D008252:Macaca fascicularis; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril; D000803:Angiotensin I; C052555:spirapril; D007703:Peptidyl-Dipeptidase A; D001920:Bradykinin