Seasonal fluctuations of androgen-binding activity in the testis of the frog, Rana esculenta.
An androgen-binding activity has been identified in nuclear extracts of the testis of the frog, Rana esculenta. A single class of high affinity (Kd = 2.5 +/- 0.6 x 10(-9) M), low-capacity binding sites was found. The binding was specific for androgens; 17 beta-estradiol displaced [3H]testosterone with an ID50 of 0.1 microM. Cytosolic binding activity has a low affinity and a high capacity and lacks specificity. The seasonal fluctuations in binding capacity did not correlate with the androgen peaks in plasma and testes between February and June and in September; periods coinciding with the resumption of spermatogenesis and the development of spermatids, respectively. The present data strongly support androgenic control of intratesticular function in vertebrates generally.
Paolucci
M
M
Dipartimento di Zoologia, Naples, Italy.
D'Antonio
M
M
Pierantoni
R
R
D000728:Androgens / Q000097:blood / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D004958:Estradiol / Q000378:metabolism; D008297:Male; D011893:Rana esculenta; D012621:Seasons; D013347:Subcellular Fractions / Q000378:metabolism; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism
D000728:Androgens; D013739:Testosterone; D004958:Estradiol