Cellular organization and neuronal inducer (inhibitor) in Xenopus adenohypothesis.

腺垂体由两个不同的部分组成，远侧部和中间部，两者都来自一个共同的胚胎雏形，称为Rathke囊，并由下丘脑调节。然而，远侧部和中间部的控制机制是不同的。远侧部的激素产生细胞由下丘脑神经元通过下丘脑-垂体血管产生的下丘脑激素控制，而中间部的促黑素细胞直接由下丘脑神经元控制。这些机制的证据是位于远侧部的大量血管，而在中间部，血管几乎没有那么发达，并且还有许多轴突穿透中间部。这样的组织学观察创造了一个工作假设，即中间部产生一些诱导神经元的因子，而远侧部分泌一些诱导神经元的因子。 ...更多信息 诱导血管的形态发生。为了确定这些因素，我试图建立一个体外生物测定系统，用于定量从下丘脑神经元投射到中间部的轴突的存在和长度。将爪蟾蝌蚪下丘脑视交叉上核与发育相同阶段的中间部或成年蟾蜍的中间部在胶原基质中共培养，并在固定的孵育期内计数从视交叉上核生长的轴突数量。当视交叉上核与远侧部或中间部共培养时，我观察到轴突生长的轻微差异，但观察的数量和可重复性较低。在研究非洲爪蟾中间部促黑素细胞特性的过程中，我发现激素原转化酶PC 1和PC 2参与了阿黑皮素原通过使用针对哺乳动物酶的特异性抗体进行蛋白水解加工成α-MSH。少

The adenohypophysis consists of two distinct parts, the pars distalis and the pars intermedia, both derived from a common embryonic rudiment called Rathke's pouch and regulated by the hypothalamus. However, the control mechanisms of the pars distalis and the pars intermedia are different from each other. Hormone-producing cells in the pars distalis are controlled by hypothalamic hormones produced by hypothalamic neurons carried via hypothalamo-hypophysial blood vessels, whereas the melanotrope cells in the pars intermedia are controlled directly by the hypothalamic neurons. Evidence of these mechanisms is the great number of blood vessels located in the pars distalis, whereas in the pars intermedia, the blood vessels are not nearly so well developed, and also by the many axons penetrating the pars intermediate. Such histological observations create a working hypothesis that the pars intermedia produces some factors that induce neurons, whereas the pars distalis secretes some factors in … More ducing morphogenesis of blood vessels. To identify these factors, I have tried to establish an in vitro bioassay system for quantitating the presence and length of the axons projecting from hypothalamic neurons into the pars intermedia. I co-cultured suprachiasmatic nuclei from hypothalamus of Xenopus tadpoles in collagen-matrix with pars intermedia from identical stages of development or from the adult toad, and counted the number of axons growing from the superchiamatic nuclei a fixed period of incubation. I observed a slight difference in the outgrowth of the axons when the suprachiasmatic nuclei were co-cultured with either the pars distalis or the pars intermedia, but the quantity and reproducibility of the observation were low. In the course of studies on the characterization of melanotrope cells in the Xenopus pars intermedia, I have found that the prohormone convertases PC1 and PC2 are involved in the proteolytic processing of proopiomelanocortin into alpha-MSH by using specific antibodies against the mammalian enzymes. Less