Danzo B J, Eller B C
Endocrinology. 1985 Oct;117(4):1380-8. doi: 10.1210/endo-117-4-1380.
Androgen-binding protein (ABP) can be detected in the blood of sexually immature male rats by its ability to specifically bind [3H]5 alpha-dihydrotestosterone (5 alpha-DHT). Since the androgen-binding site is functional, we consider this ABP to be biologically active. ABP can be detected (641 +/- 107 ng/ml; n = 5) in plasma by the 15th day of postnatal life, it reaches a maximum concentration (1631 +/- 323 ng/ml; n = 5) on day 20 of age, and is no longer detectable after day 40. ABP can be detected in the testes of all age groups studied (15 days to adult). However, no ABP is detectable in the epididymis until the animals are 25 days old. Plasma ABP comigrates on nondenaturing gels with photolabeled ABP from the adult or immature rat epididymis. Serum that had been treated with Affigel blue to remove albumin and with hydroxylapatite to decolorize it was photolabeled using [3H]17 beta-hydroxy-4,6-androstadien-3-one. Photolabeled serum ABP migrated on polyacrylamide gels containing sodium dodecyl sulfate as 60,000 and 48,000 dalton androgen-specific peaks. In contrast, photolabeled adult epididymal ABP exhibited the 47,000 and 41,000 dalton peaks characteristic of ABP subunits. When photolabeled plasma and epididymal ABP were combined and electrophoresed on the same gel under denaturing conditions, prominent 60,000 and 47,000 dalton peaks were obtained, indicating that the two species of ABP retained their identities when combined. Photolabeled epididymal ABP from 25-day-old rats exhibited similar subunit mol wt in the same ratios as ABP from the adult. When epididymal ABP from the two age groups was combined and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the resulting pattern was identical to that obtained when the samples were run individually, except that there was an increase in peak height. These data indicated that there is no significant difference in the subunit mol wt of epididymal ABP from the two age groups.
通过雄激素结合蛋白（ABP）特异性结合[3H]5α-二氢睾酮（5α-DHT）的能力，可以在性未成熟雄性大鼠的血液中检测到ABP。由于雄激素结合位点具有功能，我们认为这种ABP具有生物活性。在出生后第15天，血浆中即可检测到ABP（641±107 ng/ml；n = 5），在20日龄时达到最高浓度（1631±323 ng/ml；n = 5），40日龄后则无法检测到。在所研究的所有年龄组（15天至成年）的睾丸中均可检测到ABP。然而，直到动物25日龄时，附睾中才检测到ABP。血浆ABP在非变性凝胶上与成年或未成熟大鼠附睾的光标记ABP共迁移。用Affigel蓝处理以去除白蛋白并用羟基磷灰石使其脱色的血清，使用[3H]17β-羟基-4,6-雄甾二烯-3-酮进行光标记。光标记的血清ABP在含有十二烷基硫酸钠的聚丙烯酰胺凝胶上迁移，呈现出60,000和48,000道尔顿的雄激素特异性峰。相比之下，光标记的成年附睾ABP呈现出ABP亚基特有的47,000和41,000道尔顿峰。当光标记的血浆和附睾ABP在变性条件下在同一凝胶上合并并电泳时，获得了突出的60,000和47,000道尔顿峰，表明两种ABP在合并时保留了它们的特性。25日龄大鼠的光标记附睾ABP表现出与成年ABP相似的亚基分子量比例。当将两个年龄组的附睾ABP合并并进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳时，所得图谱与单独运行样品时相同，只是峰高有所增加。这些数据表明，两个年龄组的附睾ABP亚基分子量没有显著差异。
