AJP - Endocrinology and Metabolism, Vol 250, Issue 4 470-E474, Copyright © 1986 by American Physiological Society
Pituitary-dependent and -independent secretion of CS caused by bacterial endotoxin in rats
S. Suzuki, C. Oh and K. Nakano
Injection of bacterial endotoxin [lipopolysaccharide (LPS)] or
immobilization stress increased serum levels of ACTH with a concomitant
increase in the levels or corticosterone (CS) of rats. LPS also caused a
significant increase in the serum CS levels of hypophysectomized rats. In
contrast, immobilization stress-induced CS release was abolished completely
in these rats. Injection of histamine, a possible mediator of LPS-induced
CS secretion, provoked a significant increase in the serum CS levels of
hypophysectomized rats. Neither histamine nor LPS had any appreciable
effect on production or release of CS by cultured adrenal cells. These
results suggest that LPS-induced CS secretion is largely dependent on
hypophysial ACTH release but it also depends, in part, on an extrapituitary
mechanism and that the LPS-induced pituitary-independent secretion of CS is
mediated by histamine produced in the peripheral tissues. On the other
hand, stress-provoked CS secretion is absolutely dependent on the
pituitary-adrenocortical system.
