Seasonal fluctuations of estrogen-binding activity in the testis of the frog, Rana esculenta

• Published in: General and comparative endocrinology Vol. 75; no. 1; pp. 157 - 161
• Main Authors: Fasano, S., Pierantoni, R., Minucci, S., Di Matteo, L., Chieffi, G.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.07.1989; Elsevier
• Subjects: Animals; Biological and medical sciences; Estrogens - metabolism; Estrogens - physiology; Fundamental and applied biological sciences. Psychology; Male; Mammalian male genital system; Morphology. Physiology; Rana esculenta; Rana esculenta - metabolism; Receptors, Estrogen - metabolism; Seasons; Testis - metabolism; Testis - physiology; Testis - ultrastructure; Vertebrates: reproduction; Vertebrata; Frog; Seasonal variation; Estrogen; Rana esculenta; Amphibia; 17β-Estradiol; Salientia; Binding site; Testicle; Male genital system
• ISSN: 0016-6480; 1095-6840
• DOI: 10.1016/0016-6480(89)90021-X

We have studied the annual cycle of estrogen-binding activity in the frog, Rana esculenta, testis to evidence possible fluctuations. The testicular binding for [ 3H]estradiol-17β shows high affinities (cytosolic K d = 1.94 ± 0.43 × 10 −9 M; nuclear K d = 2.72 ± 1.20 × 10 −9 M) and low capacity (cytosolic: 7.56 ± 0.66 fmol/mg protein; nuclear: 9.27 ± 2.5 fmol/mg protein). Nuclear-binding activity appears in spring concomitantly with the estradiol peak in plasma and testes, while, in the remaining periods, binding capacity was extremely low or absent. Present data strongly support an important role played by estrogens as an intratesticular control factor in vertebrates.