Schoknecht P A, McGuire M A, Cohick W S, Currie W B, Bell A W
Department of Animal Science, Cornell University, Ithaca, NY 14853-4801, USA.
Domest Anim Endocrinol. 1996 Nov;13(6):519-28. doi: 10.1016/s0739-7240(96)00090-2.
To test the hypothesis that placental lactogen (PL) is a humoral regulator of fetal growth, six singleton sheep fetuses received a continuous intravenous fusion of 1.2 mg/d of purified ovine PL (oPL) for 14 d, beginning on Day 122 of gestation. The plasma concentration of oPL was approximately four-fold higher in infused fetuses than in six control fetuses that received a continuous infusion of saline. The circulating insulin-like growth factor 1 (IGF-I) concentration was also significantly elevated in PL-infused fetuses (43.1 +/- 1.7 vs. 31.9 +/- 4.1 ng/ml; P < 0.05). Animals were slaughtered on Day 136, and the placenta and all major fetal tissues were dissected, weighed, and subsampled for chemical analysis. Fetal weight and crown-rump length were not significantly affected by treatment; however, the aggregate weight of the brain, liver, lungs, and heart tended to be larger (85.3 +/- 2.1 vs. 79.9 +/- 1.5 g/kg fetus; mean +/- SE, P = 0.07) and the thyroid gland was smaller (0.18 +/- 0.1 vs. 0.26 +/- 0.02 g/kg fetus; P < 0.05) in the PL-infused fetuses. The livers of the PL-infused fetuses had also accumulated additional glycogen (13.1 +/- 1.7 vs. 8.4 +/- 0.7 g; P < 0.05). In late gestation, PL within the fetal compartment increases fetal plasma IGF-I concentration and hepatic glycogen deposition and may affect the growth of several vital organs.
为了验证胎盘催乳素（PL）是胎儿生长的体液调节因子这一假说，从妊娠第122天开始，对6只单胎绵羊胎儿进行了为期14天的连续静脉输注，每天输注1.2毫克纯化的绵羊PL（oPL）。与6只接受连续生理盐水输注的对照胎儿相比，输注oPL的胎儿血浆中oPL浓度大约高四倍。在输注PL的胎儿中，循环胰岛素样生长因子1（IGF-I）浓度也显著升高（43.1±1.7对31.9±4.1纳克/毫升；P<0.05）。在第136天宰杀动物，解剖胎盘和所有主要胎儿组织，称重并取子样本进行化学分析。治疗对胎儿体重和顶臀长度没有显著影响；然而，输注PL的胎儿中，脑、肝、肺和心脏的总重量往往更大（85.3±2.1对79.9±1.5克/千克胎儿；平均值±标准误，P=0.07），甲状腺较小（0.18±0.1对0.26±0.02克/千克胎儿；P<0.05）。输注PL的胎儿肝脏中还积累了更多的糖原（13.1±1.7对8.4±0.7克；P<0.05）。在妊娠后期，胎儿体内的PL会增加胎儿血浆IGF-I浓度和肝脏糖原沉积，并可能影响几个重要器官的生长。
