title: The ontogeny of immunoreactive beta-endorphin and beta-lipotropin in the rat testis.
abstract: We have investigated the ontogeny of immunoreactive beta-endorphin (i-beta E) in the testes of rats from 5 to 150 days of age. i-beta E was measured by RIA in acid extracts of decapsulated testes and characterized by gel filtration chromatography. Significant age-related differences in both the levels and type of i-beta E were observed. Total levels of i-beta E in the testes were very low and barely detectable from 5-20 days of age, but rose sharply in parallel with testes weights from 20-60 days of age; thereafter, no significant changes in i-beta E were found through 150 days of age. Concentrations of i-beta E, expressed in pmol/g testis, fell precipitously between days 5 and 10 and remained relatively constant from 10-150 days. Most of the i-beta E at 5 and 15 days chromatographed like authentic beta-endorphin. However, with the onset of puberty (30-35 days) and during sexual maturation, much of the total i-beta E chromatographed like its' precursor beta-lipotropin (beta LPH). Hypophysectomy decreased the weight and total i-beta E levels of the testes to the same extent without altering the concentrations of i-beta E or the chromatographic pattern of i-beta E. These results indicate that beta E-like and beta LPH-like peptides are present in the rat testis and that age-related changes in both the levels and type of i-beta E correlate with various structural and functional aspects of testicular development.
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: M L
authors.initials: ML
authors.lastname: Adams
authors.forename: T J
authors.initials: TJ
authors.lastname: Cicero
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D002850:Chromatography, Gel; D007016:Hypophysectomy; D008297:Male; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012741:Sexual Maturation; D013737:Testis / Q000254:growth & development*; D001615:beta-Endorphin / Q000378:metabolism*; D008083:beta-Lipotropin / Q000378:metabolism*
chemical_list: D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D008083:beta-Lipotropin