Effect of chymotrypsin on rat blood pressure.
1. Chymotrypsin (Cht) administration (14 mg/kg, i.v.) to rats always caused hypertension; hypotension preceded this effect in 64% of the observations (n = 11). 2. A 68% reduction of circulating kininogen but not of angiotensinogen was observed after Cht administration. 3. Cht effects were not affected by captopril, [Sar1-Leu8]-angiotensin II and alpha-adrenoceptor antagonists. In 70% of the observations (n = 10) hypotension was abolished by a mixture of histamine H1- and H2-antagonists. Therefore histamine release may explain hypotension. 4. Cht released in vitro from rat plasma, a substance producing hypertension in the rat and contraction of the guinea-pig ileum. Both effects were antagonized by [Sar1-Leu8]-angiotensin II. 5. In spite of this angiotensin release in vitro, the hypertensive component of the in vivo response to Cht seems to be due to some other substance.
Hiraichi
E
E
Instituto Butantan, Serviço de Farmacologia, São Paulo, Brazil.
Schiripa
L N
LN
Yamanouye
N
N
Abdalla
F M
FM
Picarelli
Z P
ZP
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000808:Angiotensinogen / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001798:Blood Proteins / Q000378:metabolism; D001810:Blood Volume / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology; D002918:Chymotrypsin / Q000494:pharmacology*; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D007704:Kininogens / Q000097:blood; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D051381:Rats; D012083:Renin / Q000378:metabolism; D012504:Saralasin / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D001798:Blood Proteins; D007704:Kininogens; D000808:Angiotensinogen; D002216:Captopril; D002918:Chymotrypsin; D012083:Renin; D012504:Saralasin