Release of renal prostaglandins during endotoxin-induced hypotension

The appearance of prostaglandins in dog's blood during endotoxin-induced hypotension was studied by use of the dialysis modification of the blood bathed organ technique. An increase in prostaglandins, mainly E2 and F2alpha was found in renal venous blood, whereas no such increase was seen in blood from the abdominal aorta, the inferior vena cava or the femoral vein. Three possible trigger mechanisms for this increase i.e. hypotension, reduced flow and reflexogenic sympathetic stimulation, have been investigated. It is suggested that, in addition to these three factors, circulating hormones such as noradrenaline, angiotensin or bradykinin, play a role in this release mechanism. Administration of indomethacin produced a restoration of the systemic blood pressure to its pre-endotoxin value; concomitantly a disappearance of the prostaglandins from the circulation was observed. It is concluded that prostaglandins contribute to the hypotension induced by endotoxin. Whether they are beneficial or detrimental remains to be resolved.