Androgen-genesis of rat testis in vivo
The effects of gonadotrophin (HCG) and hypophysectomy on androgen-genesis of rat testis, in vivo were studied. As a precursor, progesterone-4-C14 was injected intravenously to eviscerated rats under various conditions and radioactive steroids were analyzed qualitatively and quantitatively in the testis, blood and other tissues.Results obtained are summarized as follows:1. Relative high concentration of total radioactivity is found in the sexual accessory glands, especially in the preputial gland, however, none of them contains testosterone (Table. 1 & 2.).2. Testosterone is detected in the testis and blood, not onlyin adult rats but also in the HCG treated 30-day old rats, however, the presumedintermediates from progesterone, ie. 17α-hydroxyprogesterone and androstenedione, are not detectable throughout the experiments (Table. 2 & 3).4. When theanimal possesses normal testosterone-genesis system (abb. TGS), HCG accelerates it promptly and increases either production and secretion of testosterone or utilization of progesterone. Four weeks after hypophysectomy, production of testosterone ceases and progesterone is scarcely util-ized and found in a high concentration in the testis, due to impairment of TGS. The capacity of immediate response to HCG is completely lost by this time and no testosterone is produced even if a large dosage of HCG is given. Impaired TGS, however, can be restored by administrations of HCG for a considerable long period even in 10 weeks after hypophysectomy, and production and secretion of test-osterone are observed being accompanied with utilization of progesterone. (Table 3.).4. Among unidentifiedsteroids, a compound designated as [Pregnenolone] is formed from progesterone and found in the most of tissues analyzed. This is separated from Peak A (Fig.. 1) by acetylation and moves to a less-polar region than pregn-4-ene-20-α-ol-3-one-acetate. Its mobility is identical to that of authentic pregnenolone-acetate, applied as the internal standard. Heretofore, the reaction between pregnenoloneto progesterone is regarded as a irreversible one. Therefore, further careful characterization is needed for this substance.