TY - JOUR T1 - Affinity Labeling of Angiotensin II Receptors in the Isolated Rat Uterus with a Photolabile Antagonist JF - Molecular Pharmacology JO - Mol Pharmacol SP - 210 LP - 214 VL - 18 IS - 2 AU - Y. C. KWOK AU - G. J. MOORE Y1 - 1980/09/01 UR - http://molpharm.aspetjournals.org/content/18/2/210.abstract N2 - [4-Azidobenzoic acid1, isoleucine8]angiotensin II was synthesized by the solid phase method and purified by carboxymethyl cellulose chromatography. In the dark, this peptide acted as a potent competitive antagonist of angiotensin II on the isolated rat uterus (pA2 = 8.1). Irradiation of the tissue with ultraviolet light in the presence of the analog resulted in irreversible blockade of the response to angiotensin II but not to oxytocin. The photoaffinity labeling procedure resulted in a shift of the dose-response curve for angiotensin II without a loss of the maximum response, suggesting the existence of spare receptors for angiotensin II in uterine smooth muscle. ER -