Differential increase in forebrain and caudal neurosecretory system corticotropin-releasing factor and urotensin I gene expression associated with seawater transfer in rainbow trout, Endocrinology 146

Transfer to seawater (SW) in rainbow trout elicits an increase in plasma cortisol and a bout of anorexia. Although the corticotropin-releasing factor (CRF) system has known hy-pophysiotropic and anorexigenic properties, it is not known whether CRF-related peptides originating from either the forebrain or the caudal neurosecretory system (CNSS) play a role during SW acclimation. Therefore, we examined the ef-fects of SW transfer on food intake, plasma osmolality, hypo-thalamic-pituitary-interrenal axis activity, and the expres-sion of CRF and urotensin I (UI) in the forebrain and the CNSS. While SW transfer chronically suppressed food intake over a 2-wkperiod, it transiently increasedplasmaosmolality, ACTH, and cortisol. Similarly, 24 h after SW transfer, hypo-thalamic and preoptic area CRF mRNA levels were signifi-cantly increased but recovered to pretransfer levels withi