Insulin-induced renin release: blockade by indomethacin in the rat

1. Since prostaglandins appear to mediate adrenergically stimulated renin release, the effect of indomethacin was examined on insulin-induced renin and catecholamine release in conscious rats. Insulin (10 units/kg subcutaneously) increased plasma renin activity from 2.8 +/- 0.5 to 9.0 +/- 1.1 pmol h-1 ml-1 (P less than 0.001) while also increasing plasma adrenaline, noradrenaline and the urinary excretion of prostaglandin E2 and F2 alpha. Plasma potassium and glucose were reduced by 16 and 54% respectively. 2. Indomethacin (14 mumol/kg subcutaneously) reduced the urinary excretion of prostaglandin E2 and F2 alpha by 67 and 54% respectively, without altering the other parameters. 3. Indomethacin inhibited insulin-induced renin release by 67% (P less than 0.02) and blocked the insulin-induced increases in urinary prostaglandin E2 and F2 alpha. The insulin-induced changes in plasma catecholamines, potassium and glucose were unaltered by indomethacin. 4. These findings suggest that renal prostaglandins mediate this form of adrenergically stimulated renin release by acting at a side distal to the beta-adrenoreceptor.