Savoie S, Polychronakos C, Forest M G, Haour F, Collu R, Ducharme J R
Horm Res. 1981;15(3):167-78. doi: 10.1159/000179446.
Crossbred male and female lambs from Suffolk rams and Dorset-Finnish ewes born in January and February were studied at 1, 3, 7, 21 and 28 days of age and female lambs at 14 days. Ultradian variations in plasma luteinizing hormone (LH), prolactin (PRL) and testosterone were studied at 30-min intervals during a 4-hour period. In female lambs LH secretory peaks were observed at 7 days of age the amplitude of LH peaks increasing 8-fold between 7 and 14 days and 2-fold between 21 and 28 days. The number of secretory peaks also increased with age. Ultradian variations in PRL were observed from 1 day of age, the amplitude of the PRL peaks increasing also with age. In male lambs, LH and testosterone peaks were observed at 3 days of age, the testosterone peak being preceded by or concomitant with LH peaks. The amplitude of LH peaks increased with age together with basal testosterone levels although the amplitude of testosterone peaks was unchanged. This study demonstrates pulsatile secretion of LH and PRL in lambs of both sexes and of testosterone in male lambs in the first week of postnatal life. In addition, since the ovine testis is responsive to endogenous gonadotropic stimulation at this period, it is suggested that the hypothalamic-pituitary-gonadal axis is already operative at this age. It can be concluded that the hypothalamic activity concerned with pulsatile LH and prolactin secretion is present very early in the lamb neonate.
对1月和2月出生的萨福克公羊与多塞特-芬兰母羊杂交的公母羔羊进行研究，研究对象包括1日龄、3日龄、7日龄、21日龄和28日龄的羔羊，以及14日龄的母羔羊。在4小时内每隔30分钟对血浆促黄体生成素（LH）、催乳素（PRL）和睾酮进行超日节律变化研究。在母羔羊中，7日龄时观察到LH分泌高峰，LH高峰的幅度在7至14日龄之间增加8倍，在21至28日龄之间增加2倍。分泌高峰的数量也随年龄增加。从1日龄开始观察到PRL的超日节律变化，PRL高峰的幅度也随年龄增加。在公羔羊中，3日龄时观察到LH和睾酮高峰，睾酮高峰先于或与LH高峰同时出现。LH高峰的幅度随年龄增加，同时基础睾酮水平也增加，尽管睾酮高峰的幅度没有变化。本研究证明了出生后第一周内，两性羔羊的LH和PRL以及公羔羊的睾酮呈脉冲式分泌。此外，由于此时绵羊睾丸对内源性促性腺激素刺激有反应，提示下丘脑-垂体-性腺轴在这个年龄已经开始发挥作用。可以得出结论，与LH和催乳素脉冲式分泌有关的下丘脑活动在羔羊新生儿期很早就存在。
