The agouti gene codes for agouti signaling protein (ASP), which is temporally expressed in wild-type mouse follicular melanocytes where it induces pheomelanin synthesis. Studies using purified full-length agouti signaling protein has shown that it competes with (&agr;)-melanocyte stimulating hormone for binding to the melanocortin 1 receptor. We have investigated whether ASP binds exclusively t...

Ana Belén Gómez-SanMiguel1, Ana Isabel Martín1, Maria Paz Nieto-Bona2, Carmen Fernández-Galaz1, María López-Menduiña1, María Ángeles Villanúa1, Asunción LópezCalderón1. 1 Department of Physiology, Faculty of Medicine, Complutense University of Madrid. 28040 Madrid, Spain. 2 Department of Histology, Faculty of Health Sciences, Rey Juan Carlos University. Av. de Atenas s/n, 28922 Alcorcón, Madrid...

Porcine /3-melanocyte-stimulating hormone and angiotensin II were examixied as acceptors in the reaction catalyzed by arginyl-tRNA-protein transferase. Both inhibited enzymatic transfer of [l%]arginine from tRNA to bovine albumin. Inhibition was competitive with albumin and the Ki values were, respectively, 15 and 0.8 PM. The expected arginylated compounds were isolated and characterized. &Mela...

Hyporesponsive genetic variants of the melanocortin 1 receptor result in pigmentary phenotypes exhibiting light skin and light color hair, including red hair. These variants are common in populations with high rates of multiple sclerosis, while rare in populations with low rates. Alpha-melanocyte stimulating hormone, the major ligand for this receptor, is responsible for phenotype determination...

It is well known that the pineal gland hormone melatonin has a direct effect on pigment dispersion in amphibian melanocytes. This pineal hormone has also been reported to influence pituitary melanocyte-stimulating hormone (MSH) activity in the rat. Melatonin is formed from serotonin (5-hydroxytryptamine) in two metabolic steps: first, serotonin is enzymatically metabolized by N-acetyltransferas...