Renal organic anion secretion: evidence for dopaminergic and
adrenergic regulation.
Halpin, Patricia A., and J. Larry Renfro.
Department of Physiology and Neurobiology, University of
Connecticut, Storrs, Connecticut, 06269
APStracts 3:0199R, 1996.
To examine possible regulatory control of renal proximal tubule
organic anion secretion, winter flounder (Pleuronectes americanus)
proximal tubule primary cultures were mounted in Ussing chambers.
Unidirectional fluxes of 14C-2,4-dichlorophenoxyacetic acid were
determined under short-circuited conditions. Phorbol 12-myristate 13
-acetate (PMA, 1 [mu]M) caused a significant (P < 0.01)
inhibition of net 2,4-D secretion. Preincubation with staurosporine
(1 [mu]M) blocked the PMA induced decrease in secretion. Neither
forskolin (10 [mu]M) nor W-7 (20 [mu]M) had any effect on net
transport. Elevation of intracellular calcium activity with either
A23187 or thapsigargin produced a slight, transient decrease in
transport. Addition of dopamine (1 [mu]M) to the peritubular side,
but not the luminal side, caused a significant (P< 0.01)
decrease in net secretion. Both a-adrenergic agonist, oxymetazoline
(10 [mu]M), and depletion of intracellular Na+, transiently, but
significantly (P < 0.05) increased net transport. The data
indicate that renal organic anion excretion may be regulated through
dopaminergic inhibition and [alpha]-adrenergic stimulation of net
transepithelial secretion.
Received 18 March 1996; accepted in final form 13 May 1996.
APS Manuscript Number R164-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 June 96