The distal nephron of rat kidney: a target site for glucagon.

Abstract
Glucagon-sensitive adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activity was measured in 9 different portions of the rat nephron. Each sample contained a single piece of tubule isolated by microdissection from collagenase-treated kidney tissue. Compared to basal activity, 1 .mu.M porcine glucagon stimulated adenylate cyclase 60-fold in the medullary portion and 40-fold in the cortical portion of the thick ascending limb, 23-fold in the early distal convoluted tubule, 11-fold in the cortical collecting tubule, and 8-fold in the medullary collecting tubule. No stimulation was observed in proximal tubules and thin segments of the loop of Henle. Half-maximal stimulations were obtained with .apprx. 10 nM glucagon in the responsive nephron portions.