Effects of AVP and dDAVP on PGE2 synthesis in superfused cortical collecting tubules.

Whereas interactions between antidiuretic hormone (ADH) and prostaglandins (PGs) have been reported in the cortical collecting tubule (CCD), the precise effects of arginine vasopressin (AVP) and its analogue, 1-desamino-8-D-arginine vasopressin (dDAVP) on PGE2 synthesis remain controversial. We examined the dynamic response of PGE2 synthesis to these two analogues in isolated rabbit CCD. Microdissected CCD were superfused, and basal and hormone-induced PGE2 synthesis were determined by enzyme immunoassay. Addition of arachidonic acid (AA) steeply increased basal PGE2 synthesis, in the 0-1 microM-dose range. The presence of AA was necessary to obtain a stimulatory effect of AVP on PGE2 synthesis. AVP induced an immediate, transitory, and dose-dependent stimulation of PGE2 synthesis. A maximal effect was obtained at 10(-8) M; PGE2 synthesis was increased by approximately 150-200% over the basal synthesis. With dDAVP, a very weak response was obtained only at 10(-7) M. From these results, we conclude that PGE2 synthesis in CCD is stimulated by ADH. This effect of ADH does not depend on the V2-receptor pathway and suggests the presence of V1-receptors in CCD.