Substances with alpha-melanotropin-like immunoreactivity in bovine brains.
1. Bovine cerebral hemispheres were extracted with an acidic medium (acetone-water-hydrochloric acid mixture, 40:5:1 by volume, pH 1.8). The precipitate which formed upon addition of a copious volume of cold acetone to the extract was designated acid acetone powder (AAP). 2. The AAP was then subjected to ion exchange chromatography on carboxymethyl (CM)-cellulose, gel filtration on Sephadex G100 and Sephadex G25, second ion exchange chromatography on CM-cellulose and high performance liquid chromatography. The absorbance of all fractions was measured at 280 nm and their alpha-melanotropin-(alpha-MSH)-like immunoreactivity was monitored with radioimmunoassay. 3. It was found that alpha-MSH-like immunoreactivity and bioactivity (lipolytic activity) was due to low molecular weight materials as evidenced by their retardation on Sephadex G-100 and Sephadex G-25. The immunoreactivity was distributed among fractions adsorbed and fractions unadsorbed on CM-cellulose and also among high performance liquid chromatographic fractions signifying the presence of multiple alpha-MSH-like molecules.
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Department of Biochemistry, Faculty of Medicine, Chinese University of Hong Kong, Shatin, New Territories.
D000818:Animals; D001681:Biological Assay; D001923:Brain Chemistry; D002417:Cattle; D002853:Chromatography, Liquid; D011817:Rabbits; D011863:Radioimmunoassay; D000521:alpha-MSH / Q000032:analysis*
D000521:alpha-MSH