Feix M, Hoch M
Institut für Zoophysiologie der Universität Bonn, Entwicklungsbiologie, Germany.
Anasthesiol Intensivmed Notfallmed Schmerzther. 2002 Nov;37(11):651-8. doi: 10.1055/s-2002-35121.
Classically hormones are defined as molecules that are secreted by endocrine glandular or neurosecretory cells into the blood stream and transported to their target tissue where they induce physiological processes at very low concentrations. Studies on the potential origin and the evolution of cell-to-cell communication systems suggest that exocrine pheromones (food signals and toxins) might have been the primitive bioregulatory molecules of unicellular organisms for chemical communication with each other and with the biosphere. The broad distribution and the structural diversity of pheromones suggests that these molecules and their receptors were predecessor modules of cell communication systems in metazoa. Neurosecretory cells, as we find them in Cnidarians, possibly served as basic modules for the evolution of neurohormonal systems of higher animals. Studies on genetic model organisms, such as Drosophila or the mouse, have demonstrated that chemical communication between neighbouring or more distant cells does not just involve endocrine and neurosecretory cells, but also unexpectedly tissues and organs such as the heart or the adipose tissue (e. g. the leptin signalling pathway). Comparative endocrinology could show that molecular components of hormonal systems represent signalling networks that are generally used during cellular communication processes and the differentiation of cell types during ontogenesis. Some of their functions are evolutionarily conserved, others not, as disscussion on steroid hormones and the prolactin signalling pathway will demonstrate.
传统上，激素被定义为由内分泌腺或神经分泌细胞分泌到血流中，并运输到其靶组织的分子，在那里它们以极低的浓度诱导生理过程。对细胞间通讯系统潜在起源和进化的研究表明，外分泌信息素（食物信号和毒素）可能是单细胞生物用于彼此之间以及与生物圈进行化学通讯的原始生物调节分子。信息素的广泛分布和结构多样性表明，这些分子及其受体是后生动物细胞通讯系统的前身模块。我们在刺胞动物中发现的神经分泌细胞，可能是高等动物神经激素系统进化的基本模块。对果蝇或小鼠等遗传模式生物的研究表明，相邻或更远距离细胞之间的化学通讯不仅涉及内分泌和神经分泌细胞，还意外地涉及心脏或脂肪组织等组织和器官（例如瘦素信号通路）。比较内分泌学表明，激素系统的分子成分代表了在细胞通讯过程和个体发育过程中细胞类型分化时普遍使用的信号网络。正如关于类固醇激素和催乳素信号通路的讨论将表明的那样，它们的一些功能在进化上是保守的，而另一些则不是。
