Neuroendocrine Unit, Massachusetts General Hospital, Boston, 02114, USA.
Am J Physiol Endocrinol Metab. 2012 Apr 1;302(7):E800-6. doi: 10.1152/ajpendo.00598.2011. Epub 2012 Jan 17.
Amenorrhea is common in young athletes and is associated with low fat mass. However, hormonal factors that link decreased fat mass with altered gonadotropin pulsatility and amenorrhea are unclear. Low levels of leptin (an adipokine) and increased ghrelin (an orexigenic hormone that increases as fat mass decreases) impact gonadotropin pulsatility. Studies have not examined luteinizing hormone (LH) secretory dynamics in relation to leptin or ghrelin secretory dynamics in adolescent and young adult athletes. We hypothesized that 1) young amenorrheic athletes (AA) would have lower LH and leptin and higher ghrelin secretion than eumenorrheic athletes (EA) and nonathletes and 2) higher ghrelin and lower leptin would be associated with lower LH secretion. This was a cross-sectional study. We examined ghrelin and leptin secretory patterns (over 8 h, from 11 PM to 7 AM) in relation to LH secretory patterns in AA, EA, and nonathletes aged 14-21 yr. Ghrelin and leptin were assessed every 20 min and LH every 10 min. Groups did not differ for age, bone age, or BMI. However, fat mass was lower in AA than in EA and nonathletes. AA had lower LH and higher ghrelin pulsatile secretion and AUC than nonathletes and lower leptin pulsatile secretion and AUC than EA and nonathletes. Percent body fat was associated positively with LH and leptin secretion and inversely with ghrelin. In a regression model, ghrelin and leptin secretory parameters were associated independently with LH secretory parameters. We conclude that higher ghrelin and lower leptin secretion in AA related to lower fat mass may contribute to altered LH pulsatility and amenorrhea.
闭经在年轻运动员中很常见，与低体脂率有关。然而，将低体脂率与改变促性腺激素脉冲分泌和闭经联系起来的激素因素尚不清楚。瘦素（一种脂肪因子）水平降低和饥饿素（一种随着体脂减少而增加的食欲激素）增加会影响促性腺激素脉冲分泌。研究尚未检查黄体生成素（LH）分泌动力学与青春期和年轻成年运动员的瘦素或饥饿素分泌动力学之间的关系。我们假设 1）年轻闭经运动员（AA）的 LH 和瘦素分泌较低，而促性腺激素释放激素（GnRH）分泌较高，高于月经正常运动员（EA）和非运动员，2）较高的促性腺激素释放激素（GnRH）和较低的瘦素与较低的 LH 分泌有关。这是一项横断面研究。我们检查了 AA、EA 和非运动员中促性腺激素释放激素（GnRH）分泌模式与 ghrelin 和 leptin 分泌模式之间的关系，年龄为 14-21 岁。每 20 分钟评估一次 ghrelin 和 leptin，每 10 分钟评估一次 LH。组间年龄、骨龄或 BMI 无差异。然而，AA 的体脂率低于 EA 和非运动员。AA 的 LH 和促性腺激素释放激素（GnRH）脉冲分泌和 AUC 较高，瘦素脉冲分泌和 AUC 较低，而非运动员和 EA。体脂百分比与 LH 和瘦素分泌呈正相关，与促性腺激素释放激素（GnRH）呈负相关。在回归模型中，ghrelin 和 leptin 分泌参数与 LH 分泌参数独立相关。我们得出结论，AA 中较高的促性腺激素释放激素（GnRH）和较低的瘦素分泌与较低的体脂率相关，可能导致 LH 脉冲分泌和闭经改变。
