Differential functions of hypothalamic galanin cell grows in the regulation of eating and body weight.

Evidence suggests that hypothalamic galanin (GAL) has a variety of functions related to energy and nutrient balance, reproduction, water balance, and neuroendocrine regulation. The focus of this chapter is the role of GAL in eating and body weight regulation. Findings described herein demonstrate that GAL, in a cell group of the anterior region of the paraventricular nucleus (aPVN) that projects to the median eminence, has a role in the control of fat intake, fat metabolism, and body fat. This function of aPVN GAL neurons is carried out in close relation to circulating insulin and glucose. Galanin-expressing perikarya in the medial preoptic area (MPOA) have a similar function, although GAL here operates in association with the female steroids estrogen and progesterone. These GAL cell groups of the aPVN and MPOA contrast with those in the arcuate nucleus as well as the magnocellular vasopressin-containing neurons of the PVN and supraoptic nucleus, which show no relation to fat balance. This evidence reveals differential functions for the distinct GAL neuronal cell groups of the hypothalamus.