Distribution of prostaglandin E 2-sensitive adenylate cyclase along the rat nephron

Abstract

To define sites of prostaglandin action of renal tubules, the distribution of adenylate cyclase sensitive to prostaglandin E 2 (PGE 2) was examined in single nephron segments dissected from rat kidney. Further, the interaction between PGE 2 and vasopressin on adenylate cyclase activity in nephron segments sensitive to vasopressin was evaluated. Procedures involved in isolating nephron segments were without effects on adenylate cyclase stimulation by PGE 2. PGE 2 stimulated adenylate cyclase activity of the thin descending limb of Henle (tDL), cortical collecting tubules (CCT), and medullary collecting tubules (MCT) at concentrations of 1.4 × 10 −5 to 2.8 × 10 −5 M. PGE 2 was without effects in other nephron segments tested including proximal convoluated tubules, proximal pars recta, the thin and thick ascending limb of Henle's loop, and distal and connecting tubules. PGE 2, at both high (2.8 × 10 −5 M) and low (2.8 × 10 −8 M) concentrations, did not inhibit adenylate cyclase activity stimulated by submaximal doses of vasopressin in medullary thick ascending limb of Henle (MTAL), CCT, and MCT. These data define the distribution of PGE 2-sensitive adenylate cyclase in the rat nephron, i.e., tDL, CCT, and MCT, and show the lack of direct inhibitory actions of PGE 2 on vasopressin sensitive adenylate cyclase in MTAL, CCT, and MCT.