Downregulation of corticotropin-releasing factor mRNA, but not vasopressin mRNA, in the paraventricular hypothalamic nucleus of rats following nutritional stress.

Stress can cause disturbance of homeostasis to result in illness. Stress can also induce various gene expression in different neuronal systems. For example, nutritional stress induced by acute food deprivation upregulates corticotropin-releasing factor (CRF) mRNA, whereas osmotic stress increases vasopressin (VP) mRNA. However, it is unknown if nutritional stress induced by chronic food deprivation has synergistic effects on CRF and VP mRNAs. We have used in situ hybridization in conjunction with quantitative autoradiography to demonstrate that nutritional stress induced by a 4-day food deprivation results in a body-weight loss with a significant decrease of CRF mRNAs, but not VP mRNAs in the paraventricular hypothalamic nucleus (PVN) of Sprague-Dawley rats. The present study has thus indicated that a chronic nutritional stress does not have synergistic effects on CRF and VP mRNAs. The decrease of CRF mRNAs is obviously related to the body-weight loss induced by food deprivation. This study thus supports a notion that the CRF, but not VP, neurons in the PVN play an important role in their neuroadaptation associated with body weight loss. Thus, it is conceivable that downregulated CRF neurons in the hypothalamus could be involved in pathogenesis of human eating disorder with severe weight loss, whereas upregulated CRF neurons could be associated with an opposite form of the eating disorder that causes obesity.