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.
Instituto Butantan, Serviço de Farmacologia, São Paulo, Brazil.
E
E
Hiraichi
L N
LN
Schiripa
N
N
Yamanouye
F M
FM
Abdalla
Z P
ZP
Picarelli
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