Islami D, Bischof P, Chardonnens D
Department of Obstetrics and Gynaecology, Clinic of Infertility and Gynaecological Endocrinology, WHO Collaborating Centre in Human Reproduction, University Hospital of Geneva, 32 Boulevard de la Cluse, 1211, Geneva, Switzerland.
Eur J Obstet Gynecol Reprod Biol. 2003 Oct 10;110(2):169-75. doi: 10.1016/s0301-2115(03)00185-4.
Leptin is a metabolic signal to the reproductive axis, where it increases the plasma levels of luteinising hormone (LH) and follicle stimulating hormone (FSH). Since the placental regulation of human chorionic gonadotrophin (hCG) mimics that of the pituitary LH, we undertook this study to see if leptin could be involved in the secretion and synthesis of hCG in first-trimester trophoblast. We incubated cytotrophoblastic cells (CTB) with GnRH-I or GnRH-II, for 4 or 48 h and collected the media at different times thereafter. GnRH-II was more potent than GnRH-I when incubated for 4 h with CTB. Leptin secretion, as measured at 4 h, was significantly stimulated by GnRH-II. When measured at 24 h leptin values were also increased as compared to controls. Neither GnRH-I, nor GnRH-II had any effect on leptin secretion when incubated for 48 h with CTB. Leptin was also added to perifused placental explants, and samples (in which hCG was measured) were collected every 3 min. Leptin significantly stimulated hCG secretion by explants and induced a pulse of hCG immediately (within 6 min) after its injection, increasing significantly the area under the curve (P=0.04) and the amplitude (P=0.02) of hCG pulses. We conclude that GnRH-II is more effective than GnRH-I in stimulating leptin secretion. This difference could be explained by the existence of two different types of placental GnRH receptors or two different pathways of GnRH degradation. Furthermore, we observe that leptin has a significant stimulatory effect on hCG pulsatility.
瘦素是一种作用于生殖轴的代谢信号，它可提高黄体生成素（LH）和卵泡刺激素（FSH）的血浆水平。由于人绒毛膜促性腺激素（hCG）的胎盘调节作用类似于垂体LH，我们开展了这项研究，以探究瘦素是否参与孕早期滋养层细胞中hCG的分泌与合成。我们将细胞滋养层细胞（CTB）与GnRH-I或GnRH-II孵育4或48小时，之后在不同时间收集培养基。与CTB孵育4小时时，GnRH-II比GnRH-I更有效。在4小时时检测发现，GnRH-II可显著刺激瘦素分泌。在24小时时检测，与对照组相比，瘦素值也有所升高。当与CTB孵育48小时时，GnRH-I和GnRH-II对瘦素分泌均无任何影响。我们还将瘦素添加到灌注的胎盘外植体中，每3分钟收集一次样本（检测其中的hCG）。瘦素可显著刺激外植体分泌hCG，并在注射后立即（6分钟内）诱导hCG脉冲，显著增加hCG脉冲的曲线下面积（P=0.04）和幅度（P=0.02）。我们得出结论，在刺激瘦素分泌方面，GnRH-II比GnRH-I更有效。这种差异可能是由于存在两种不同类型的胎盘GnRH受体或两种不同的GnRH降解途径。此外，我们观察到瘦素对hCG的脉冲性有显著的刺激作用。
