McVey Mark J, Cooke Gerard M, Curran Ivan H A
Reproductive Biology Unit, Departments of Cellular and Molecular Medicine and Obstetrics and Gynecology, University of Ottawa, Ottawa, ON, Canada.
Reprod Toxicol. 2004 Jul;18(5):677-85. doi: 10.1016/j.reprotox.2004.04.005.
The consequences of dietary soy isoflavones on serum and testicular androgen levels were examined in F1 male rats from a multigeneration study investigating the effects of diets varying in isoflavone content. Rats were fed either a soy-free casein based diet (AIN93G) or a diet in which alcohol-washed soy protein replaced casein as the protein source and to which increasing amounts of Novasoy, a commercially available isoflavone supplement were added. Analysis of these diets showed that the isoflavone content in each diet was 0 (diet 1; casein based control), 31.7 (diet 2; alcohol-washed soy-based diet control), 36.1 (diet 3), 74.5 (diet 4), 235.6 (diet 5) and 1046.6 (diet 6) mg total isoflavones/kg pelleted diet. The levels of isoflavones in diet 1 would represent a daily intake level of 0 mg isoflavones, diets 2 and 3 estimate a low soy-containing human diet (e.g. North American), diet 4 would correspond to Asian diets (e.g. Japanese) or adult humans taking isoflavone supplements, diet 5 approximates the isoflavone intake by babies fed soy based infant formula and diet 6 approximates fivefold the intake levels by babies or 10-fold the intake levels of adults consuming high isoflavone containing diets. Serum testosterone (T) from F1 male rats sacrificed on postnatal days (PND) 28, 70, 120, 240 and 360 were low at PND 28 (0.4 ng/ml), increased approximately five to sixfold at PND 70 (2.5-3.0 ng/ml) and thereafter declined to a steady state level of approximately 1 ng/ml by PND 120. However, rats on diets 5 and 6 demonstrated altered serum testosterone profiles such that at days 120, testosterone levels remained significantly elevated at approximately 3 ng/ml (P < 0.05). Serum dihydrotestosterone levels exhibited similar profiles and the levels in PND 120 rats on diet 5 or 6 were also significantly elevated (two to threefold, P < 0.05). The intra-testicular testosterone concentration in rats on diet 5 was also elevated at PND 120 compared with diet 1 (P < 0.05). These findings show that F1 male rats continuously exposed to a mixture of dietary soy isoflavones from conception onwards exhibit altered serum and testicular androgen profiles.
在一项多代研究中，研究了不同异黄酮含量饮食的影响，检测了F1雄性大鼠饮食大豆异黄酮对血清和睾丸雄激素水平的影响。给大鼠喂食不含大豆的酪蛋白基饮食（AIN93G）或用酒精洗涤过的大豆蛋白替代酪蛋白作为蛋白质来源，并添加越来越多的市售异黄酮补充剂Novasoy的饮食。对这些饮食的分析表明，每种饮食中的异黄酮含量分别为0（饮食1；酪蛋白基对照）、31.7（饮食2；酒精洗涤大豆基饮食对照）、36.1（饮食3）、74.5（饮食4）、235.6（饮食5）和1046.6（饮食6）毫克总异黄酮/千克颗粒饲料。饮食1中的异黄酮水平代表每日0毫克异黄酮的摄入量，饮食2和3估计为低大豆含量的人类饮食（如北美饮食），饮食4相当于亚洲饮食（如日本饮食）或服用异黄酮补充剂的成年人，饮食5近似于喂食大豆基婴儿配方奶粉的婴儿的异黄酮摄入量，饮食6近似于食用高异黄酮饮食的婴儿摄入量的五倍或成年人摄入量的十倍。在出生后第28天（PND）、70天、120天、240天和360天处死的F1雄性大鼠的血清睾酮（T）在PND 28时较低（0.4纳克/毫升），在PND 70时增加约五到六倍（2.5 - 3.0纳克/毫升），此后到PND 120时降至约1纳克/毫升的稳定水平。然而，饮食5和6组的大鼠血清睾酮水平出现改变，在120天时，睾酮水平显著升高至约3纳克/毫升（P < 0.05）。血清双氢睾酮水平呈现相似的变化趋势，饮食5或6组PND 120大鼠的双氢睾酮水平也显著升高（两到三倍，P < 0.05）。与饮食1组相比，饮食5组大鼠在PND 120时睾丸内睾酮浓度也升高（P < 0.05）。这些发现表明，从受孕开始持续暴露于饮食大豆异黄酮混合物中的F1雄性大鼠，其血清和睾丸雄激素水平出现改变。
