Regulation of human erythrocyte na+/h+-exchange by soluble and
particulate guanylate cyclase.
Petrov, Victor, and Paul Lijnen.
Hypertension Unit, Department of Molecular and Cardiovascular
Research, University of Leuven (KULeuven), Leuven, Belgium.
APStracts 3:0224C, 1996.
The existence of gyanylate cyclase activity in human erythrocytes is
investigated in the present study by evaluating the intracellular
cGMP content in the presence of various agents that exert specific
effects on soluble or particulate guanylate cyclase. The increase in
the intraerythrocyte cGMP content by the soluble guanylate cyclase
activators, nitroprusside and sodium nitrite, suggests the presence
of this enzyme in human erythrocytes. The effects of four different
ANP-fragments on the intraerythrocyte cGMP content is also studied.
ANPII and ANPIII increase the intraerythrocyte cGMP content while
ANPI and des-Ser5,des-Ser6-ANPIII are ineffective. Thus, our data
show that human erythrocytes possess particulate guanylate cyclase
together with the soluble enzyme. The ANP-fragments ANPII and ANPIII
also activate the erythrocyte Na+/H+-exchange. Nitroprusside, M&B
22,948 (an inhibitor of cGMP phosphodiesterase), and the cGMP
analogs, dibutyryl-cGMP and 8-Br-cGMP also increase the erythrocyte
Na+/H+-exchange rate. The latter data also suggest that the
erythrocyte Na+/H+-exchange is regulated by cGMP.
Received 20 June 1994; accepted in final form 15 May 1996.
APS Manuscript Number C348-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996