Wiebe J P, Barr K J, Buckingham K D
J Toxicol Environ Health. 1982 Oct-Nov;10(4-5):653-66. doi: 10.1080/15287398209530284.
Sprague-Dawley rats were injected sc with lead acetate in suspension, or with sodium acetate (controls) on the d 9 of pregnancy and every 3-4 d thereafter until the pups were 13 or 21 d of age. At termination, testicular homogenates or isolated Sertoli cells were used to study steroidogenesis and gonadotropin binding. Lead had no significant effect on the mother's water and food consumption, on the pup's body or testis weights, on the number of pups and the time of birth, and on the seminiferous tubule diameter. Homogenates of testes of the lead-treated group converted significantly less (p less than 0.01) labeled progesterone (14C or 3H) to 5 alpha-pregnane-3,20-dione, 3 alpha-hydroxy-5 alpha-pregnan-20-one, 17 beta-hydroxy-5 alpha-androstan-3-one (DHT), 3(alpha, beta)-hydroxy-5 alpha-androstan-17-one, testosterone/17 alpha-hydroxyprogesterone, and androstenedione. Sertoli cells from lead-treated animals converted significantly less (p less than 0.01) progesterone to 5 alpha-pregnane-3 alpha, 20 alpha-diol, 3 alpha-hydroxy-5 alpha-pregnan-20-one, DHT, and 20 alpha-hydroxy-4-pregnen-3-one. These data and direct spectrophotometric assays indicated that 3 alpha-hydroxysteroid oxidoreductase (3 alpha-HSO), 3 beta-HSO, 20 alpha-HSO, 5 alpha-reductase, and C17-20-lyase had been affected. The receptor studies showed that the binding of [125I]rFSH to testicular receptors was significantly reduced from 35,600 (control) to 25,980 cpm/mg protein (lead). This is the first evidence that lead exposure (in utero and via mother's milk) significantly reduces steroid production and hormone binding in the testis at the onset of puberty.
在妊娠第9天,给Sprague-Dawley大鼠皮下注射醋酸铅悬浮液,或注射醋酸钠(作为对照),此后每3 - 4天注射一次,直至幼崽13或21日龄。实验结束时,取睾丸匀浆或分离的支持细胞用于研究类固醇生成和促性腺激素结合情况。铅对母体的水和食物摄入量、幼崽的体重或睾丸重量、幼崽数量和出生时间以及曲细精管直径均无显著影响。铅处理组睾丸匀浆将标记的孕酮(14C或3H)转化为5α-孕烷-3,20-二酮、3α-羟基-5α-孕烷-20-酮、17β-羟基-5α-雄甾烷-3-酮(双氢睾酮)、3(α,β)-羟基-5α-雄甾烷-17-酮、睾酮/17α-羟基孕酮以及雄烯二酮的量显著减少(p小于0.01)。铅处理动物的支持细胞将孕酮转化为5α-孕烷-3α,20α-二醇、3α-羟基-5α-孕烷-20-酮、双氢睾酮以及20α-羟基-4-孕烯-3-酮的量也显著减少(p小于0.01)。这些数据和直接分光光度测定表明,3α-羟基类固醇氧化还原酶(3α-HSO)、3β-羟基类固醇氧化还原酶(3β-HSO)、20α-羟基类固醇氧化还原酶(20α-HSO)、5α-还原酶以及C17-20裂解酶均受到影响。受体研究表明,[125I]重组促卵泡激素(rFSH)与睾丸受体的结合量从35,600(对照)显著降低至25,980 cpm/mg蛋白质(铅处理组)。这是首个证据表明,孕期和通过母乳接触铅会在青春期开始时显著降低睾丸中的类固醇生成和激素结合。