Biological and immunological characterization of corticotropin-releasing activity in the bovine adrenal medulla.
Corticotropin-releasing factor (CRF)-like activity in bovine adrenal medulla extracts were characterized by measurement of adrenocorticotropin (ACTH) release from rat anterior pituitary cells in vitro, and by a sensitive heterologous radioimmunoassay (RIA) for bovine hypothalamic CRF. Bovine adrenal medulla was boiled in 2 M acetic acid, homogenized, and submitted to acetone precipitation, followed by batch-wise treatment with C-18 resin. The partially purified adrenal medulla extract showed significant stimulation of ACTH release in vitro and CRF-like immunoreactivity (CRF-IR). After subsequent ion exchange chromatography on a SP-Sephadex column, most CRF bioactivity (CRF-BA) and CRF-IR were eluted with weakly basic materials in the SP-II fraction in which synthetic CRF is eluted. Minor CRF-BA and CRF-IR were also eluted in the SP-III fraction which contained basic peptides. Upon Sephadex G-50 gel filtration of the SP-II fraction, CRF-BA and CRF-IR coeluted, but slightly later than synthetic bovine CRF. However, rechromatography of the major CRF activity on a Sephadex G-50 column and reverse phase and ion exchange high performance liquid chromatographies (HPLC) indicated that CRF-BA and CRF-IR were eluted in the identical fraction as synthetic bovine CRF. Gel filtration in the SP-III fraction on a Sephadex G-50 column showed a few low CRF-BA peaks which lacked CRF-IR. This CRF-BA, however, contributed to less than 5% of the total CRF-BA. These results indicate that the majority of CRF-BA and CRF-IR in the bovine adrenal medulla is chromatographically indistinguishable from bovine hypothalamic CRF.(ABSTRACT TRUNCATED AT 250 WORDS)
Minamino
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U.S.-Japan Biomedical Research Laboratories, Tulane University Hebert Center, Belle Chasse, LA 70037.
Uehara
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Arimura
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A
D000313:Adrenal Medulla / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis / Q000276:immunology; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003346:Corticotropin-Releasing Hormone / Q000096:biosynthesis* / Q000276:immunology / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism; D066298:In Vitro Techniques; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism; D011863:Radioimmunoassay
D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone