Urotensin I, a CRF-like neuropeptide, stimulates acth release from the teleost pituitary.

Intraperitoneal injections of urotensin I, a CRF-like neuropeptide isolated from the caudal neurosecretory system of the teleost Catostomus commersoni, ovine CRF and sauvagine all produced significant increases in circulating levels of plasma cortisol in goldfish in which endogenous ACTH secretion was suppressed with betamethasone. In vitro, urotensin I was 2-3 times more potent than CRF or sauvagine in stimulating ACTH release from a superfused goldfish anterior pituitary cell column. These results demonstrate that urotensin I stimulates ACTH release in the goldfish, which suggests that urotensin I or a urotensin I-like peptide may serve as a CRF in teleost fishes.