Direct evidence for the presence of a different converting enzyme in the hamster cheek pouch.
Kininase II (angiotensin I-converting enzyme) is generally accepted to be the enzyme responsible for the conversion of angiotensin I (A I) to angiotensin II (A II). This study examined the response of the microvasculature of the hamster cheek pouch to the local application of A I, A II, and the renin substrate, tetradecapeptide (TDP). A I and TDP caused a localized vasoconstriction that was not blocked by converting enzyme inhibitors (CEI: BPF5a for A I and BPF5a and the nonapeptide inhibitor for TDP). However, both the A II antagonist [Sar1, Ala8]angiotensin II and the antiserum to A II blocked completely the A I- and TDP-induced vasoconstriction. Sixty-eight percent of the applied A I was converted to A II in the presence of CEI as well as in its absence. It is concluded that the vasculature of the hamster cheek pouch converts significant amounts of A I to A II by a route that does not involve kininase II.
D000803:Angiotensin I / Q000378:metabolism* / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D000809:Angiotensins / Q000378:metabolism*; D000818:Animals; D002610:Cheek / Q000201:enzymology; D006224:Cricetinae; D005260:Female; D009842:Oligopeptides / Q000494:pharmacology; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D014661:Vasoconstriction / Q000187:drug effects
D000809:Angiotensins; D009842:Oligopeptides; D000804:Angiotensin II; D000803:Angiotensin I; D007703:Peptidyl-Dipeptidase A