Oxygen dependence of respiration in coupled and uncoupled
endothelial cells.
Steinlechner-Maran, Rosmarie, Thomas Eberl, Marie-Luise Kunc, Raimund
Margreiter, and Erich Gnaiger.
Department of Transplant Surgery, University Hospital of Innsbruck,
Anichstra[beta]e 35, A-6020 Innsbruck, Austria
APStracts 3:0207C, 1996.
We studied the oxygen dependence of respiration in cultured human
umbilical vein endothelial cells (HUVEC) using high-resolution
respirometry. The rate of oxygen consumption varied from 30 to 50
pmol O2 per second per 106 cells over a six-fold range of cell
densities. Respiration was stimulated up to 3.5-fold by uncoupling
with FCCP or 2,4-DNP, and the p50 increased from 0.05 to 0.12 kPa
(0.3 to 0.9 Torr) with respiratory rate. p50 decreased to a minimum
of 0.02 kPa when uncoupled cells were inhibited to control levels.
Differences in cell size explained a variation of c. 0.015 kPa in p50
at similar respiratory rates per cell. Oxygen diffusion to
mitochondria contributed maximally 30% to the regulation of p50 in
coupled cells, as deduced from the shallow slope of the flux
-dependence of p50 in uncoupled/inhibited cells compared to the slope
in coupled cells. Therefore, 70% of the flux-dependence of p50 in
coupled cells were caused by changes in metabolic state which
correlated with respiratory rate.
Received 19 December 1995; accepted in final form 20 June 1996.
APS Manuscript Number C754-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 July 96