[Effect of indomethacin on renin secretion in isolated perfused rat kidney (author's transl)]

In vivo administration of indomethacin (I) is associated with a decrease in basal and stimulated plasma renin activity in man and other animal species including the rat. In order to identify the mechanism(s) underlying the effect of I on renin secretion, studies were carried out using isolated rat kidneys perfused at a constant rate (5 ml/min) with cell-free medium. In this model, the infusion of I into the renal artery at concentrations ranging from 5.5 to 167 mumol/1 induced a dose-dependent and reversible increase in renal renin release. Although these effects were observed without variation in perfusion pressure and kidneys were non-filtering, no definitive conclusion may be drawn concerning their mediation by macula densa or baroreceptors from the present data. Inhibition of renal prostaglandin biosynthesis by I may play a role; however, another possible mechanism could be the inhibition of phosphodiesterase activity by I. Supporting this view was the finding that theophylline, a potent known inhibitor of phosphodiesterase activity mimicked the effect of indomethacin in our model.