AJP - Endocrinology and Metabolism, Vol 245, Issue 5 515-E520, Copyright © 1983 by American Physiological Society
Effects of housing and chronic cannulation on plasma ACTH and corticosterone in the rat
K. D. Fagin, J. Shinsako and M. F. Dallman
Effects of housing and cannulation on plasma ACTH and corticosterone levels
were evaluated to validate a method for obtaining repeated blood samples
for ACTH from conscious rats. Resting morning, evening, or noise-stimulated
(4 min of metal rattling) levels of plasma ACTH or corticosterone obtained
by decapitation were similar in rats housed alone or in pairs. Individually
housed, cannulated rats had slightly elevated morning levels of plasma ACTH
and corticosterone, but the evening and noise-stimulated increases in
hormone levels were similar to those in unoperated, decapitated rats. A
hemorrhage stimulus administered on separate days to cannulated rats evoked
highly replicable elevations in plasma ACTH and corticosterone. These
results demonstrate that 1) ACTH and corticosterone secretion are similar
in rats housed alone versus in pairs, and 2) long-term cannulation permits
multiple intra-animal comparisons of basal and acutely stimulated plasma
ACTH and corticosterone levels that are useful reflections of those
measured in decapitated rats.
