The effect of exercises on the content and reception of the steroid hormones in rat skeletal muscles.

Two peaks of hormone concentration in blood and skeletal muscles (SM) were found, immediately after intensive physical exercises (PE) and the late period of rest. Immediately after PE testosterone (T) and estradiol (E2) concentration in SM increased on 36 and 430%, returning to the initial level in 2 h. E2 and androstenedione content in SM increased from 33 +/- 7 to 89 +/- 3 and from 563 +/- 58 to 767 +/- 38 pg/g tissue accordingly in 48 h, returning to the initial level in 72 h. T content increased in blood 3.7-fold in SM 2.2-fold in 72 h after PE. Androgen receptor (AR) contents in SM cytosol increased (on 28%) in 2 h, then returned to the control level and increased again in 72 h (from 0.6 +/- 0.4 to 1.2 +/- 0.2 fmol/mg protein) after PE. Kd did not change significantly and were 0.33 +/- 0.03 nM. The experiments on female rats showed the same tendency, but T increasing was more marked compared to male rats. The obtained results showed that the hormonal regulation of metabolic processes in SM has a cyclic character and is connected with the changing of hormonal content and hormonal SM receptors.