Bovine adrenal endothelial cells express nucleoside transporters
non-regulated by protein kinases a and c.
Sen, R. P., Sobrev[acute]ia, L., Delicado, E. G., Yudilevich, D. and
Miras-Portugal M. T.
DEPARTMENT OF BIOCHEMISTRY. FACULTAD DE VETERINARIA. UNIVERSIDAD
COMPLUTENSE. 28040 MADRID. SPAIN, DEPARTMENT OF PHYSIOLOGY, AND
BIOPHYSICS, FACULTAD DE MEDICINA. UNIVERSIDAD DE CHILE. P. O. BOX
70005 SANTIAGO. CHILE.
APStracts 3:0028C, 1996.
The present investigation characterizes the nucleoside transporters in
bovine adrenomedullary endothelial cells (BAMEC) and their possible
regulation by the action of protein kinases A and C in order to
establish comparisons with the nucleoside transport system in
chromaffin cells. The nucleoside transport proved to be a NBTI
-sensitive-facilitated diffusion system with high affinity for
adenosine. These endothelial cells had a high density of nucleoside
transporters (660,000 +/- 130,000 transporters/cell), measured by
NBTI binding, and the efficiency was close to 2 molecules of
adenosine internalized/transporter/second. The stimulation of the
cells with bradykinin and Ap4A, which raise the intracellular Ca2+
concentration, did not modulate the adenosine transport. When the
cells were stimulated with signals coupled to cAMP intracellular
production, such as noradrenaline and isoproterenol, the adenosine
transport was not modified. Futhermore, the treatment of the cells
with direct activators of both protein kinases A and C had no effect
on adenosine transport, in contrast to that reported in chromaffin
cells.
Received 25 July 1995; accepted in final form 19 January 1996.
APS Manuscript Number C456-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 January 96