Size of cell nuclei in hypothalamus of the rat as a function of salt loading

Abstract

Rats were given only 2% saline to drink ad libitum for 10 days. A control group drank tap water ad libitum. The hypothalami were then sectioned, and the volumes of 200 cell nuclei were determined in each animal for each of the following nuclei: posterior, ventromedial, dorsomedial, and arcuate (over 8,000 nuclei measured in a total of 14 rats). The distribution of cell nuclear volume size showed a statistically significant decrease only in the posterior hypothalamic nucleus. In the other nuclei, cell nuclear size increased to an insignificant degree. It is suggested, in concert with other evidence, that the posterior nucleus of the hypothalamus may have a neuroendocrine function.