EFFECT OF UROCORTIN AND ITS INTERACTION WITH ADRENOCORTICOTROPIN (ACTH) SECRETAGOGUES ON ACTH RELEASE

We examined the effect of urocortin (Ucn) on the adrenocorticotropin ( ACTH) release from cultured rat anterior pituitary cells and AtT 20 ce lls. Synthetic rat (r)Ucn was not soluble in 0.1 N HCl but soluble in alkaline solvents with diminished corticotropin-releasing activity. rU cn dissolved in 0.1 M sodium phosphate buffer as a stock solution main tained its bioactivity and had the equal corticotropin-releasing activ ity with rat/human corticotropin-releasing factor (r/hCRF). rUcn stimu lated the adrenocorticotropin release via CRF-receptors accompanied by the additive effect with r/hCRF, the synergistic effect with arginine vasopressin and the dose-dependent inhibition of a potent CRF-recepto r antagonist. (C) 1998 Elsevier Science Inc.