Neuroendocrine interactions between galanin, opioids, and neuropeptide Y in the control of reproduction and appetite.

Galanin is a pleiotropic neuroendocrine signal produced in discrete subpopulations of neurons distributed in several sites in the hypothalamus. Neuropeptide Y and beta-endorphin also display pleiotropism, but they are produced by subpopulations of neurons located only in the arcuate nucleus of the hypothalamus. Each of these neuropeptides exerts a regulatory influence on reproduction and appetitive behavior. Experimental and morphologic evidence from our laboratory show direct contacts and interplay among these diverse signals. Seemingly, an interconnected network composed of these three neuropeptide-producing neurons provides precision and site specificity in the relay of information necessary to govern reproduction and appetite. Disruptions in this interplay are likely to manifest in untoward consequences such as infertility and obesity.