Journal of Andrology, Vol. 25, No. 6, November/December 2004
Copyright © American Society of Andrology
Rapid Glucocorticoid Mediation of Suppressed Testosterone Biosynthesis in Male Mice Subjected to Immobilization Stress
QIANG DONG,
ANTONIO SALVA,
CHANTAL M. SOTTAS,
ENMEI NIU,
MICHAEL HOLMES AND
MATTHEW P. HARDY
From the Center for Biomedical Research, Population Council, and the
Rockefeller University, New York, New York.
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Correspondence to: Dr Matthew P. Hardy, Center for Biomedical Research,
Population Council and The Rockefeller University, 1230 York Ave, New York, NY
10021. |
Physical and psychosocial stress challenge homeostasis, increasing
glucocorticoid secretion (in rodents, corticosterone [CORT]) while decreasing
testosterone (T) levels. The dynamics of stress-induced changes in T, CORT,
and luteinizing hormone (LH) concentrations in mice have not been investigated
previously. In particular, it remains to be established whether there is a
rapid effect of CORT that is directly mediated by glucocorticoid receptors
(GRs) in the testis. Therefore, serum and intratesticular T, serum CORT, and
LH levels were measured during acute immobilization (IMO) stress, using the
C57BL/6 strain of mice. The effects of testicular GR blockade were
investigated by administration of the GR antagonist, RU486, via
intratesticular (IT) or intraperitoneal (IP) injection. CORT levels increased
in stressed males starting at 15 minutes, reaching a fivefold higher plateau
by 1 hour compared with controls (P < .01). Conversely, starting from 30
minutes on, both serum and intratesticular T levels decreased in stressed
males to 30% and 8% of control values, respectively, by 6 hours (P < .01).
In contrast, LH was unchanged by IMO stress for up to 6 hours. Intratesticular
treatment with RU486 partially prevented the IMO-induced decline in T levels.
CORT treatment reduced intracellular cyclic adenosine monophosphate (cAMP)
content in Leydig cells by 15 minutes and T production by 30 minutes in vitro.
We conclude that 1) the rapid changes in T suggest a suppression of T
biosynthesis by glucocorticoid through a nongenomic mechanism, lowering the
production of cytoplasmic cAMP; 2) changes in gonadotropic stimulation of
Leydig cells are unlikely to explain the suppression of T levels during acute
stress; and 3) the results are consistent with a direct inhibitory action of
CORT on Leydig cells.
Key words: Leydig cell, cyclic AMP, glucocorticoid receptor
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Copyright © 2004 by The American Society of Andrology.