pEC50: 11.46 (human CRF 1 , CHO cells), 9.36 (human CRF 2 , CHO cells), 9.85 (rat CRF 2α , CHO cells) Ki: 0.4 nM (hCRF 1 , cell assay), 1.8 nM (rCRF 2α , cell assay), and 5.7 nM (mCRF 2β , cell assay)
Urotensin I is 2-3 times more potent than CRF or sauvagine in stimulating ACTH release from a superfused goldfish anterior pituitary cell column. Rat tail artery strips were incubated in the presence of 4 x 10(-3) M theophylline and Urotensin I (UI). At the concentrations of 1.50, 7.50 mU/ml but not of 0.75 mU/ml Urotensin I, the content of cAMP increased significantly.
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.