[Vasopressin action sites along the nephron (author's transl)]

Sites of action of vasopressin along the nephron were investigated by using a microassay for adenylate cyclase for single pieces of tubule microdissected from collagenase-treated kidneys. In the rabbit, not only the medullary and cortical portions of collecting tubules, but also the thin and thick segments of the ascending limb of Henle's loop were observed to contain adenylate cyclase highly responsive to arginine-vasopressin. In contrast, the other segments of the nephron-including the descending limb of the loop, the distal convolution, and the connecting tubule -- were unresponsive to vasopressin. Qualitative and quantitative species difference were noted between rabbit, rat, mouse and man, regarding vasopressin responsiveness in distal tubules and ascending limbs. As an example, adenylate cyclase in thick ascending limb is not sensitive to vasopressin in man whereas, in rat, it is as responsive as the collecting tubule. The physiological relevance of these results is discussed.