Wilkinson M, Younglai E V
Biol Reprod. 1986 Oct;35(3):572-8. doi: 10.1095/biolreprod35.3.572.
In neurochemical terms, little is known concerning the control of puberty onset in the female rabbit. In view of the established involvement of brain opiates in the sexual maturation of the rat, we have investigated the prepubertal development of opiate-binding sites in the hypothalamus and cerebral cortex of the rabbit. Binding of the opiate antagonist, [3H] naloxone, to thick (350 micron) slices of rabbit brain was found to be reversible, stereospecific, saturable, and of high affinity. In all respects these sites possessed the characteristics of opiate receptors. Specific binding (Bmax and KD) values were determined at 1, 8, 29, 40, 51, 100, and 168 days after birth in the hypothalamus and cerebral cortex. All all ages binding in the hypothalamus was higher, per mg of tissue, than in the cortex. Major differences in the pattern of development were also evident. In the cortex the Bmax slowly increased from a minimum at Day 1 to a maximum at about 100 days when puberty normally occurs. In contrast, binding in the hypothalamus rose rapidly to a maximum at 40 days and then fell abruptly, by about 40% at Day 51, after which a slow increase through puberty took place. This peak in the hypothalamic Bmax value correlates closely with the major prepubertal surge of gonadotropin secretion. It remains to be determined whether the coincidence of spontaneous gonadotropin secretion with the rapid appearance of hypothalamic opiate receptors is developmentally meaningful for the reproductive system.
从神经化学角度来看，关于雌性兔青春期启动的控制所知甚少。鉴于已证实脑内阿片类物质参与大鼠的性成熟过程，我们研究了兔下丘脑和大脑皮质中阿片类物质结合位点的青春期前发育情况。发现阿片类拮抗剂[³H]纳洛酮与兔脑厚（350微米）切片的结合是可逆的、立体特异性的、可饱和的且具有高亲和力。在所有方面，这些位点都具有阿片受体的特征。在出生后1、8、29、40、51、100和168天测定下丘脑和大脑皮质中的特异性结合（Bmax和KD）值。在所有年龄段，每毫克组织中下丘脑的结合量均高于皮质。发育模式的主要差异也很明显。在皮质中，Bmax从第1天的最低值缓慢增加到大约100天（通常为青春期）时的最高值。相比之下，下丘脑的结合在40天迅速上升至最高值，然后在51天突然下降约40%，此后在青春期期间缓慢增加。下丘脑Bmax值的这个峰值与青春期前促性腺激素分泌的主要激增密切相关。自发性促性腺激素分泌与下丘脑阿片受体快速出现的巧合对于生殖系统在发育上是否有意义仍有待确定。
