Regional epinephrine kinetics in human heart failure: evidence for
extra-adrenal, non-neural release.
Kaye, David M, Jeff Lefkovits, Helen Cox, Gavin Lambert, Garry
Jennings, Andrea Turner, Murray D Esler.
Alfred Baker Medical Unit, Baker Medical Research Institute,
Melbourne, Australia
APStracts 2:0062H, 1995.
A number of neurohumoral processes are activated in heart failure,
including an increase in the plasma concentration of epinephrine.
Radiotracer methods were applied in 42 patients with severe heart
failure and 31 healthy volunteers, to ascertain the rate at which
epinephrine is released to plasma, and to evaluate the contribution
of extra-adrenal sources. The increase in arterial plasma epinephrine
observed in the heart failure patients was explained principally by a
34% (p<0.001) reduction in the whole body clearance rate of
epinephrine from plasma. Regional venous sampling from the heart,
lungs and hepatomesenteric beds was performed in a subgroup of the
study population, revealing a significant increase in the release
rate of epinephrine to plasma from these organs in heart failure,
which accounted for 26% of the whole body plasma epinephrine
appearance rate. To establish whether the cardiac epinephrine release
was of neuronal origin, a physical (cycling) or mental (difficult
mental arithmetic) stressor was applied as a sympathoexcitatory
stimulus, given that a proportional release of norepinephrine and
epinephrine could be expected if sympathetic nerves were the source.
These interventions caused significant increases in the regional
spillover of norepinephrine to plasma, but not that of epinephrine.
These findings suggest that non-adrenal tissues contribute
significantly to the whole body epinephrine release rate in heart
failure, and that this may arise from a site other than sympathetic
neurons.
Received 3 January 1994; accepted in final form 17 February 1995.
APS Manuscript Number H002-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 March 1995.