1. In order to test whether the release of E-type prostaglandins from the kidney by various vasoconstrictor stimuli is related specifically to adrenoreceptor activation, we have compared release of prostaglandin E-like material from perfused rat kidneys during infusion of noradrenaline or vasopressin.
2. Concentrations of noradrenaline or vasopressin that produced comparable rises in renal perfusion pressure also released comparable amounts of prostaglandin E-like material. This effect was abolished by infusion of an inhibitor of prostaglandin synthesis into the kidney.
3. We conclude that liberation of E-type prostaglandins during renal vasoconstriction is probably related to the activation of intra-renal smooth muscle and does not involve any specific hormonal receptor. Stimulation of release of prostaglandin E may explain certain reported renal actions of vasopressin.