Release of a prostaglandin E-like substance into mixed venous blood during endotoxin hypotension in cats.
An iv injection of E. coli endotoxin (10--15 mg/kg) produced biphasic hypotensive reaction in cats. The second phase of hypotension developed 5--10 min after the administration of endotoxin and was paralleled by an appearance of a substance contracting the chick rectum and rat colon which were bathed in mixed venous blood. On the basis of differential sensitivity of the assay organs to prostaglandins it was concluded that a prostaglandin E-like substance (PGEs) was released. Its peak concentration in blood was 1--3-5 ng/ml in terms of PGE2-like activity. Indomethacin (10 mg/kg) interrupted the liberation of PGEs into blood and at the same time a slow but steady increase in arterial blood pressure occured. The amelioration of endotoxin hypotension by indomethacin was abolished by an infusion of PGE2 at a rate of 20--100 ng/kg/min. It is suggested that the second phase of endotoxin hypotension in cats is mediated by a release of PGEs.
D000818:Animals; D000992:Antitoxins / Q000494:pharmacology; D002415:Cats; D004731:Endotoxins / Q000494:pharmacology*; D004926:Escherichia coli / Q000032:analysis; D005260:Female; D007022:Hypotension / Q000139:chemically induced*; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D011458:Prostaglandins E / Q000097:blood*
D000992:Antitoxins; D004731:Endotoxins; D011458:Prostaglandins E; D007213:Indomethacin