Biosynthesis of a gamma 3-melanotropin-like peptide in the pars intermedia of the amphibian pituitary gland.
This study reveals the biosynthesis of a gamma 3-melanotropin-like peptide in the pars intermedia of the pituitary gland of the aquatic toad Xenopus laevis. Pulse-chase experiments in vitro showed that this product is synthesized through processing of a prohormone, pro-opiomelanocortin, and that it is released into the incubation medium. The peptide immunoprecipitated with antiserum to gamma 3-melanotropin, appeared to be a glycopeptide and displayed melanotropic activity. This last observation together with the results of tryptic and chymotryptic peptide mapping of the newly synthesized product indicates that Xenopus gamma 3-melanotropin is structurally different from the proposed mammalian gamma-melanotropins.
D000818:Animals; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D007120:Immunochemistry; D009074:Melanocyte-Stimulating Hormones / Q000096:biosynthesis*; D010452:Peptide Biosynthesis; D010902:Pituitary Gland / Q000378:metabolism*; D014982:Xenopus laevis / Q000378:metabolism
D009074:Melanocyte-Stimulating Hormones