AJP - Endocrinology and Metabolism, Vol 250, Issue 1 76-E81, Copyright © 1986 by American Physiological Society
Effect of rate of hemorrhage on release of ACTH in cats
D. A. Bereiter, A. M. Zaid and D. S. Gann
The effect of rate of blood loss by acute hemorrhage (H) on
adrenocorticotropin (ACTH) and cortisol plasma concentrations was assessed
in anesthetized cats. Arterial blood was withdrawn at a rapid rate (10%
blood vol/min) or at a slow rate (2%/min), and responses were compared
across three volumes of H (10, 20, and 30% of blood vol). After rapid rate
of H, ACTH increased in proportion to volume of H (r = 0.669, P less than
0.001) with a mean elevation of 124 +/- 27, 267 +/- 102, and 950 +/- 195
pg/ml for 10, 20, and 30% H, respectively. Slow rate of H evoked a
significant increase in ACTH that was not proportional to volume of H (r =
0.314, P greater than 0.10), and the mean change during the post-H sampling
period was 611 +/- 166, 828 +/- 302, and 1,070 +/- 239 pg/ml for 10, 20,
and 30% H, respectively. Control animals showed no change in ACTH to the
repeated sampling paradigm. Rapid H evoked an immediate decrease in mean
arterial pressure (MAP) with a post-H recovery of MAP inversely
proportionate to volume of H (r = -0.552, P less than 0.01). Slow H caused
a progressive decrease in MAP with no significant post-H recovery of MAP at
any volume of H. Cortisol concentration increased in proportion to volume
of H after rapid H (r = 0.515, P less than 0.025), but not after slow
H.(ABSTRACT TRUNCATED AT 250 WORDS)
