Binding of Steroid Hormones by the 105,000 x g Supernatant Fraction from Homogenates of Rat Skin and Variations During the Hair Cycle

The study demonstrated that the binding of steroid hormones such as testosterone, 5α-dihydrotestosterone, estradiol-17β, and progesterone by the 105,000 x g supernatant fraction from rat skin homogenates was pH-dependent and affected by heat. The binding ability varied with the hair cycle phases, with soluble protein content being highest during the anagen phase and lowest during telogen. Testosterone binding peaked in the catagen phase, while 5α-dihydrotestosterone and estradiol-17β binding peaked in telogen. Progesterone binding was consistent and did not show significant variation. The molecular weights of the binding proteins for 5α-dihydrotestosterone and estradiol-17β were estimated to be approximately 90,000 and 50,000, respectively.