Longcope C, Kato T, Horton R
J Clin Invest. 1969 Dec;48(12):2191-201. doi: 10.1172/JCI106185.
Continuous infusions of Delta(4)-androstenedione-7-(3)H and testosterone-7-(3)H have been used to demonstrate that these androgens are converted to estrone and 17beta-estradiol, and contribute to the circulating blood levels of these estrogens in normal males and females. The conversion ratio (ratio of concentrations of radioactivity of free product steroid [chi(-PRO)] and free precursor steroid [chi(-PRE)], both corrected for recoveries, after an infusion of radioactive precursor steroid) for androstenedione (precursor) to estrone (product) is 0.013 in males and 0.007 in females, and the conversion ratio for testosterone (precursor) to estradiol (product) is 0.0018 in males and 0.005 in females. The transfer constant, rho (AE1), for androstenedione conversion to estrone (rho (AE1) = per cent of infused androstenedione, precursor, converted to estrone, product, when infusion and measurement are both in blood) is 1.35% in males and 0.74% in females, and the transfer constant, rho (TE2), for testosterone conversion to estradiol is 0.39% in males and 0.15% in females. Whether measured as conversion ratio or transfer constant, the peripheral aromatization of androstenedione takes place to a greater degree than that of testosterone, and, for the respective androgens, both the conversion ratio and rho value are greater in males than females. For the androgen interconversions, rho (AT) is 4.5% in males and 2.2% in females; rho (TA) is 8.2% in males and 12.0% in females. Studies on the distribution coefficients (effective concentration in red cells/plasma) for precursor radioactivity were also made. In both males and females the distribution coefficient for androstenedione is 0.16-0.17 while that of testosterone is 0.01-0.03.
连续输注Δ⁴-雄烯二酮-7-(³H)和睾酮-7-(³H)已被用于证明这些雄激素可转化为雌酮和17β-雌二醇，并对正常男性和女性体内这些雌激素的循环血水平有贡献。雄烯二酮（前体）转化为雌酮（产物）的转化率（输注放射性前体类固醇后，游离产物类固醇[χ(-PRO)]和游离前体类固醇[χ(-PRE)]的放射性浓度之比，两者均校正回收率）在男性中为0.013，在女性中为0.007；睾酮（前体）转化为雌二醇（产物）的转化率在男性中为0.0018，在女性中为0.005。雄烯二酮转化为雌酮的转移常数ρ(AE1)（ρ(AE1)=输注的雄烯二酮前体转化为雌酮产物时，输注和测量均在血液中的百分比）在男性中为1.35%，在女性中为0.74%；睾酮转化为雌二醇的转移常数ρ(TE2)在男性中为0.39%，在女性中为0.15%。无论以转化率还是转移常数来衡量，雄烯二酮的外周芳香化程度都比睾酮更高，并且对于各自的雄激素，男性的转化率和ρ值均高于女性。对于雄激素的相互转化，ρ(AT)在男性中为4.5%，在女性中为2.2%；ρ(TA)在男性中为8.2%，在女性中为12.0%。还对前体放射性的分布系数（红细胞/血浆中的有效浓度）进行了研究。在男性和女性中，雄烯二酮的分布系数均为0.16 - 0.17，而睾酮的分布系数为0.01 - 0.03。
