title: Acetylcysteine in rats: inhibition of activation of prekallikrein and factor XII--protection against dextran-induced blood pressure fall.
abstract: Acetylcysteine (AC) injected intravenously into rats (200 mg/kg) had no effect on blood pressure, but significantly inhibited dextran-induced (40 mg/kg) blood pressure fall. Injection of AC also reversibly blocked the activation of prekallikrein (PK) normally obtained in plasma incubated with acetone. Kallikrein was assayed as plasminogen activator, S-2302 amidase and BAEe esterase. Also the activation of factor XII to factor XIIa, assayed as prekallikrein activator, was strongly inhibited in AC-treated rats. It is suggested that the partial blockade of dextran-induced shock is correlated with an inhibition of activation of PK and factor XII. Previous experiments had demonstrated an extensive, but reversible in vitro inhibition of human plasma kallikrein by AC. In view of such data it is concluded that the present results obtained with AC in rats are probably due to an inhibition of plasma kallikrein and its activation of factor XII.
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000581:Amidohydrolases / Q000032:analysis; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002265:Carboxylic Ester Hydrolases / Q000032:analysis; D003911:Dextrans / Q000037:antagonists & inhibitors; D004347:Drug Interactions; D004792:Enzyme Precursors / Q000032:analysis; D005174:Factor XII / Q000032:analysis*; D007458:Iodipamide / Q000494:pharmacology; D007610:Kallikreins / Q000032:analysis*; D008297:Male; D009842:Oligopeptides / Q000032:analysis; D010960:Plasminogen Activators / Q000097:blood; D011288:Prekallikrein / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D003911:Dextrans; D004792:Enzyme Precursors; D009842:Oligopeptides; C026148:prolyl-phenylalanyl-arginine-4-nitroanilide; D005174:Factor XII; D011288:Prekallikrein; D002265:Carboxylic Ester Hydrolases; C019763:benzoylarginine ethyl esterase; D007610:Kallikreins; D010960:Plasminogen Activators; D000581:Amidohydrolases; D007458:Iodipamide; D000111:Acetylcysteine