Cortical distribution of prostaglandin and renin in isolated dog glomeruli

This study was performed (1) to evaluate the ability of renal superficial (SP) and juxtamedullary (JM) isolated glomeruli to synthesize 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and prostaglandin E2 (PGE2) when stimulated with different doses of arachidonic acid (AA) and (2) to determine the differential effects that the formation of these prostaglandins may have on renin release. Renal SP and JM glomeruli were isolated separately from dog renal cortex using a passive sieving technique. Glomeruli were superfused within glass chambers with a Krebs Ringer solution and three different concentrations of AA. Effluent concentrations of 6-keto-PGF1 alpha (primary metabolite of PGI2), PGE2, and renin were determined by radioimmunoassay. Synthesis of 6-keto-PGF1 alpha by SP glomeruli increased in a dose-dependent manner in response to the three increasing concentrations of AA. These three doses of AA also evoked proportional increments in the release of renin which were significantly correlated with the increases in 6-keto-PGF1 alpha. In contrast, PGE2 synthesis was maximally stimulated by all doses of AA and was not correlated with renin release. In JM glomeruli, AA evoked the same pattern in the synthesis of 6-keto-PGF1 alpha and PGE2. However, renin release increased significantly only with the perfusion of the highest concentration of AA. These perfusion results show that SP and JM glomeruli have the same ability to synthesize 6-keto-PGF1 alpha and PGE2. However, renin release was significantly higher in SP than in JM glomeruli and correlated with 6-keto-PGF1 alpha synthesis.