Our aim was to investigate the effect of a single testosterone (T) injection on the an
drogen receptor (AR) in rat skeletal muscle (SM) cytosol. The properties of AR were stu
die
d in or
der to esta
blish the protocol for
differential
determination of free an
d hormone-occupie
d AR in SM cytosols from non-hormone-
deficient animals. Using the
develope
d ligan
d-exchange protocol, we
demonstrate
d that injection of T (1 mg/kg) cause
d alternating changes of the total AR
bin
ding. The
bin
ding minimum (23 % of the control) was measure
d 1 h after the injection. It was followe
d by pronounce
d an
d lasting elevation of the AR
bin
ding. In the control cytosols, AR complexes constitute
d ![]()
bor
der=0 SRC=/images/glyphs/BQ1.GIF>25 % of the total receptor content. Changes of their relative content imme
diately after T a
dministration were consistent with rapi
d nuclear translocation of the AR. Inhi
bition of protein synthesis
by cycloheximi
de (CHI) injection
demonstrate
d that
delaye
d an
d lasting increase of the AR
bin
ding after T injection partially
depen
de
d on the stimulate
d protein synthesis. Altogether, the o
btaine
d evi
dence supports the assumption that the AR me
diates elevation of its own gene expression in SM upon a
dministration of T.