Bassett N S, Gluckman P D
J Endocrinol. 1986 Jun;109(3):307-12. doi: 10.1677/joe.0.1090307.
The ontogenesis of the pulsatility of GH in the ovine fetus was determined by obtaining blood samples at 20-min intervals for 3-h periods from fetuses (n = 33) at various stages of development (76-147 days gestation), and in neonatal life (n = 19). A significant increase (P less than 0.01) in the GH mean, nadir and maximum, and pulse height was observed between the ages of 100 and 130-139 days of gestation. An analysis of the difference in the mean, maximum and nadir concentrations between 100 and 139 days of gestation revealed that males had higher GH levels than females (P less than 0.05). There was a significant fall in plasma GH concentrations from 140 days of gestation to term, but before the onset of active labour. There was a more rapid fall in the circulating levels of fetal GH directly following birth. Immediately before birth fetal GH levels were still relatively high, but within 60 min of birth they had fallen by more than 80%. It is suggested that these changes in the pulsatile pattern of GH release are a consequence of both maturational changes in the hypothalamic-pituitary unit and the effects of pregnancy-related factors on GH release. The sexually dimorphic nature of GH release in the adult is also observed in the sheep fetus during late gestation.
通过对不同发育阶段（妊娠76 - 147天）的绵羊胎儿（n = 33）以及新生羔羊（n = 19）每隔20分钟采集一次血样，每次采集3小时，来确定绵羊胎儿生长激素（GH）脉冲性分泌的个体发生情况。在妊娠100天至130 - 139天之间，观察到GH的平均值、最低点、最大值以及脉冲高度均显著增加（P < 0.01）。对妊娠100天至139天之间的GH平均浓度、最大浓度和最低浓度差异分析显示，雄性胎儿的GH水平高于雌性胎儿（P < 0.05）。从妊娠140天到足月，但在活跃分娩开始之前，血浆GH浓度显著下降。出生后，胎儿GH的循环水平下降更快。出生前即刻胎儿GH水平仍相对较高，但出生后60分钟内，其水平下降超过80%。提示GH释放脉冲模式的这些变化是下丘脑 - 垂体单位成熟变化以及妊娠相关因素对GH释放影响的共同结果。在妊娠后期的绵羊胎儿中也观察到成年期GH释放的性别二态性。
