Corticotropin/lipotropin common precursor-like material in normal rat extrapituitary tissues.
A Mr 26,000 corticotropin (ACTH)-like material is present in glacial acetic acid extracts of all normal rat extrapituitary tissues. In the present study, beta-melanotropin (beta-MSH) immunoactivity was detected in glacial acetic acid extracts of normal rat extrapituitary tissues. beta-MSH immunoactivity was also present in all extracts (mean +/- SEM, fmol/mg of protein): brain, 71.0 +/- 16.3; stomach, 11.5 +/- 1.6; kidney, 8.9 +/- 0.8; colon, 8.2 +/- 1.1; small intestine, 6.5 +/- 1.1; liver, 4.3 +/- 0.5; and heart, 3.2 +/- 0.5. Except in brain extracts, beta-MSH and ACTH immunoactivities of tissue extracts were strongly correlated to each other (r = 0.79; n = 42). When tissue extracts (except brain) were passed through a Sephadex G-75 (superfine) column, ACTH and beta-MSH immunoactivities were eluted in a single peak corresponding to Mr 26,000. In contrast, for brain extracts, the MrS of major peaks of ACTH and beta-MSH immunoactivities were 4,500 and 8,000, respectively; a smaller peak of Mr 26,000 ACTH/beta-MSH-like material was also eluted. Specific anti-ACTH immunocolumns, which did not bind purified synthetic beta-MSH, adsorbed both ACTH and beta-MSH immunoactivities of all tissue extracts except those of brain. One-third of the beta-MSH immunoactivity in brain extracts adsorbed to the anti-ACTH immunocolumn, but two-thirds of beta-MSH immunoactivity passed through the column. We conclude that ACTH and beta-MSH immunoactivities are present in all normal rat extrapituitary tissues and exist in most tissues on the same molecule. This Mr 26,000 molecule is closely related to the pituitary ACTH/beta-lipotropin common precursor.
D000818:Animals; D001923:Brain Chemistry; D004064:Digestive System / Q000032:analysis*; D007668:Kidney / Q000032:analysis*; D008099:Liver / Q000032:analysis*; D009074:Melanocyte-Stimulating Hormones / Q000032:analysis; D009206:Myocardium / Q000032:analysis*; D010902:Pituitary Gland / Q000032:analysis; D010908:Pituitary Hormones, Anterior / Q000032:analysis*; D011333:Pro-Opiomelanocortin; D011498:Protein Precursors / Q000032:analysis*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
D010908:Pituitary Hormones, Anterior; D011498:Protein Precursors; D011333:Pro-Opiomelanocortin; D009074:Melanocyte-Stimulating Hormones