Interaction of the prostaglandin and renin-angiotensin systems in isolated rat glomeruli

Abstract

Renal glomeruli were isolated from rat kidneys using a passive mechanical sieving technique. Suspensions of 40–50 mg glomeruli were placed in glass chambers and superfused by a modified Krebs-Ringer solution. Effluent collections of 10-min fractions were measured for renin or prostaglandin (PG) E2 concentration using radioimmunoassays. The perfusate was altered to contain either the beta-adrenergic agonist isoproterenol, angiotensin II, or arachidonic acid. Isoproterenol at 1.78 or 8.1 X 10(-4) M produced a significant release of renin, but the concentration of PGE2 was unaffected. Isoproterenol-stimulated renin release was blocked by 1.2 X 10(-4) M propranolol but was unaffected by 6.3 X 10(-6) M meclofenamate. Angiotensin II at 4 or 40 X 10(-9) M altered neither renin nor PGE2. Arachidonic acid administered at 1.6 or 16.0 X 10(-5) M produced a marked increase in PG synthesis and stimulated a significant release of renin. Treatment of glomeruli with 6.3 X 10(-6) M meclofenamate attenuated PGE2 synthesis and abolished renin release, but 1.2 X 10(-4) M propranolol had no effect on PG synthesis or the coincident release of renin. These results give direct evidence of an interrelating mechanism between renal prostaglandins and renin release that is independent of external tubular or hemodynamic stimuli and show that the beta-adrenergic pathway of renin stimulation is independent of any modifying influence exerted by prostaglandins.