Carlsen E, Olsson C, Petersen J H, Andersson A M, Skakkebaek N E
Department of Growth and Reproduction, Copenhagen University Hospital, Copenhagen N, Denmark.
J Clin Endocrinol Metab. 1999 May;84(5):1664-9. doi: 10.1210/jcem.84.5.5708.
Inhibin B is a testicular glycoprotein that is secreted from the Sertoli cells and believed to play a role in FSH secretion. We characterized the diurnal profile of serum inhibin B and the relation to gonadotropins and testicular steroids. Serum inhibin B was measured in 13 healthy normal male volunteers (median age, 30 yr) by continuous blood drawing, with sampling every 30 min for 24 h. Blood samples were also analyzed for FSH, LH, testosterone, estradiol, and sex hormone-binding globulin. We found a significant diurnal variation in inhibin B, with peak values in the early morning and nadirs in the late afternoon, followed by gradual increasing nocturnal values. An average decline of 3%/h from 0900 until 1700 h was calculated. Significant cross-correlation was found between inhibin B and testosterone as well as estradiol, whereas no cross-correlation was found between inhibin B and FSH. Two-dimensional time-series analyses revealed a statistically significant influence of testosterone on inhibin B. In addition, estradiol and inhibin B had a significant influence on one another. In conclusion, we found a significant diurnal variation in inhibin B levels in normal men, with a pattern of higher values in the early morning hours and lower values in the late afternoon and evening. We did not find evidence for a role of FSH in this diurnal variation of inhibin B. However, covariation with serum levels of testosterone and estradiol suggested that these hormones might play a role in the diurnal rhythm of inhibin B, although some other common influence could not be excluded.
抑制素B是一种睾丸糖蛋白，由支持细胞分泌，被认为在促卵泡激素（FSH）分泌中起作用。我们对血清抑制素B的昼夜变化及其与促性腺激素和睾丸类固醇的关系进行了特征描述。通过连续采血对13名健康正常男性志愿者（中位年龄30岁）进行血清抑制素B测定，每30分钟采样一次，共采集24小时。还对血样进行了促卵泡激素、促黄体生成素、睾酮、雌二醇和性激素结合球蛋白的分析。我们发现抑制素B存在明显的昼夜变化，清晨达到峰值，傍晚降至最低点，随后夜间值逐渐升高。计算得出从09:00到17:00每小时平均下降3%。发现抑制素B与睾酮以及雌二醇之间存在显著的交叉相关性，而抑制素B与促卵泡激素之间未发现交叉相关性。二维时间序列分析显示睾酮对抑制素B有统计学上的显著影响。此外，雌二醇和抑制素B相互之间也有显著影响。总之，我们发现正常男性中抑制素B水平存在明显的昼夜变化，清晨时段值较高，傍晚和夜间值较低。我们没有找到证据表明促卵泡激素在抑制素B的这种昼夜变化中起作用。然而，与睾酮和雌二醇血清水平的协变表明这些激素可能在抑制素B的昼夜节律中起作用，尽管不能排除其他一些共同影响因素。
