Preparation of tritiated alpha-melanotropin with high specific radioactivity.
alpha-Melanotropin (alpha-MSH) was iodinated and 3,5-diiodotyr2-alpha-MSH was isolated by reverse phase high performance liquid chromatography (HPLC). Catalytic dehalogenation of the diiodo derivative in the presence of tritium resulted in the formation of 3,5-ditritiotyr2-alpha-MSH. The tritiated peptide was purified by ion exchange and partition chromatography. The radioactive peptide was found to be homogeneous and identical to alpha-MSH by paper electrophoresis and HPLC. The tritiated alpha-MSH stimulated lipolysis in rabbit adipocytes nearly as well as alpha-MSH. The specific radioactivity of tritiated alpha-MSH was 42 Ci/mmol or 73% of the theoretical value.
D000273:Adipose Tissue / Q000187:drug effects; D000818:Animals; D001681:Biological Assay; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D007553:Isotope Labeling / Q000379:methods*; D008066:Lipolysis / Q000187:drug effects; D009074:Melanocyte-Stimulating Hormones / Q000031:analogs & derivatives / Q000302:isolation & purification / Q000494:pharmacology; D011817:Rabbits; D013552:Swine; D014316:Tritium; D000521:alpha-MSH / Q000031:analogs & derivatives*
D014316:Tritium; D000521:alpha-MSH; C024115:MSH, 2-(3,5-diiodo-Tyr)alpha-; C029460:MSH, 2-Tyr-alpha-; D009074:Melanocyte-Stimulating Hormones