AJP - Endocrinology and Metabolism, Vol 266, Issue 4 E676-E681, Copyright © 1994 by American Physiological Society
Endocrine interactions: adrenal steroids and precursors
G. T. Taylor, J. Scherrer, J. Weiss and J. Pitha
Laboratory of Psychobiology, University of Missouri, St. Louis, Missouri 63121.
Adult male rats (n = 48) were castrated and treated daily for 4 wk with
adrenal steroids in the presence or absence of adjuvant testosterone.
Dehydroepiandrosterone (DHEA), DHEA sulfate, and androstenedione (2 mg/kg
body wt) were administered as cyclodextrin complexes to mimic the
pharmacodynamics of the endogenous products. Although they are the
substrates for testosterone synthesis in target tissues, supplements of
adrenal steroids alone were unable to maintain integrity of sociosexual
responses and androgen target tissues after castration. More surprising,
groups administered adrenal precursor plus testosterone showed substantial
suppression of the typical restoration of reproductive systems in castrates
receiving androgen therapy. The adrenal steroids, however, were not
functionally identical. Each steroid interacted with testosterone to leave
its own distinctive "footprint" on androgen-sensitive systems. The
conclusion is that the endogenous adrenal products are not simply passive
precursors of testosterone. Adrenal steroids may serve as endocrine
regulators of androgen bioavailability and bioactivity.
