AJP - Cell Physiology, Vol 259, Issue 4 C693-C696, Copyright © 1990 by American Physiological Society
AVP stimulates adenylyl cyclase and phospholipase C in reciprocal fashion in cultured RIMCT cells
I. Teitelbaum and A. Strasheim
Department of Medicine, University of Colorado School of Medicine, Denver 80262.
In cultured rat inner medullary collecting tubule (RIMCT) cells, arginine
vasopressin (AVP) stimulates adenylyl cyclase (AC) activity in
dose-dependent fashion, with no response at concentrations of 10(-10) M or
below and with peak activity at 10(-7) M AVP. In contrast, AVP-stimulated
phospholipase (PLC) activity is greatest at concentrations at which there
is no effect on AC and decreases at higher concentrations of AVP, becoming
undetectable at 10(-7) M. Increasing cellular adenosine 3',5'-cyclic
monophosphate (cAMP) content with either exogenous ClPheScAMP or forskolin
eliminates inositol trisphosphate production in response to 10(-13) M AVP.
Conversely, inhibition of AC by 2',5'-dideoxyadenosine (DDA) unmasks PLC
activity in response to 10(-7) M AVP that is not observed in the absence of
DDA. Similarly, DDA prevents inhibition of epidermal growth
factor-stimulated PLC by AVP. These findings demonstrate the reciprocal
relationship between AVP-stimulated AC and PLC activities in cultured RIMCT
cells, which may explain previous divergent results regarding the ability
of AVP to stimulate PLC in this tissue.
