Vasopressin-stimulated Ca2+ reabsorption in rabbit cortical collecting system: effects on cAMP and cytosolic Ca2+.
The effect of arginine vasopressin (AVP) on transepithelial Ca2+ transport in primary cultures of rabbit cortical collecting system cells was examined. Addition of AVP to the basolateral side of the monolayer dose-dependently (EC50 = 0.7 nM) increased active Ca2+ reabsorption from a basal value of 85 +/- 2 nmol.h-1.cm-2 to a maximum value of 124 +/- 3 nmol.h-1.cm-2. This was paralleled by a dose-dependent (EC50 = 1.1 nM) increase in cellular adenosine 3', 5'-cyclic monophosphate (cAMP) content. Both effects of AVP were mimicked by the V2 agonist deamino-Cys,D-Arg8-vasopressin (dDAVP) and forskolin. Addition of either AVP or dDAVP to the basolateral side evoked a sustained increase in cytosolic free Ca2+ concentration, which resulted from both Ca2+ entry and release from internal stores. Only the effect on Ca2+ entry was mimicked by forskolin, demonstrating that cAMP acts by activating a Ca2+ influx pathway. The present findings demonstrate that AVP stimulates transcellular Ca2+ transport in the cortical collecting system through activation of basolateral V2 receptors coupled to adenylyl cyclase to increase the cellular cAMP content.
van Baal
J
J
Department of Cell Physiology, University of Nijmegen, PO Box 9101, NL-6500 HB Nijmegen, The Netherlands.
Raber
G
G
de Slegte
J
J
Pieters
R
R
Bindels
R J
RJ
Willems
P H
PH
D000042:Absorption / Q000187:drug effects; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D007672:Kidney Cortex; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011817:Rabbits
D001127:Arginine Vasopressin; D000242:Cyclic AMP; D002118:Calcium