AJP - Endocrinology and Metabolism, Vol 257, Issue 6 E866-E870, Copyright © 1989 by American Physiological Society
Atrial natriuretic factor in the elderly: diminished response to epinephrine
L. A. Morrow, G. S. Morganroth, T. J. Hill, J. A. Sanfield, S. G. Rosen, R. J. Grekin and J. B. Halter
Department of Internal Medicine, University of Michigan, Ann Arbor.
We have previously found that epinephrine (EPI) increases plasma
immunoreactive atrial natriuretic factor (irANF) in young human subjects.
Because elderly humans have decreased sensitivity to adrenergic
stimulation, we compared plasma irANF responses to intravenous infusion of
EPI, 5 micrograms/min for 80 min in six young (ages 20-29) and nine old
(ages 62-75) healthy subjects. In addition, we measured plasma irANF
responses of the nine old subjects to 1 liter of normal saline infused over
30 min. Young and old subjects had similar basal EPI levels [108 +/- 18 vs.
106 +/- 10 (SE) pg/ml], but basal irANF levels tended to be higher in the
old (32 +/- 7 vs. 50 +/- 8 pmol/l, P = 0.15). The young subjects had a
significant increase in irANF levels after the EPI infusion (32 +/- 7 vs.
59 +/- 11 pmol/l, P less than 0.02), but there was no change in irANF in
the old (50 +/- 8 vs. 48 +/- 7 pmol/l) despite similar plasma EPI levels in
young and old (1,125 +/- 57 vs. 1,183 +/- 52 pg/ml). In contrast, the irANF
response of the old subjects to saline infusion was striking: all nine
subjects demonstrated a rise in irANF (P less than 0.01); mean levels
increased from 54 +/- 4 pmol/l to a peak of 122 +/- 23 pmol/l. We conclude
that healthy elderly subjects have a defect in EPI-stimulated ANF
secretion, a finding compatible with other evidence for diminished
sensitivity to adrenergic stimulation in aging.(ABSTRACT TRUNCATED AT 250
WORDS)
