title: Characterization of neutral TRH-like peptides in mammary gland, mammary tumors and milk.
abstract: Three pyroglutamylpeptide amides, pGlu-Glu-Pro amide, pGlu-Phe-Pro amide and pGlu-Gln-Pro amide, with similar structures to thyrotropin-releasing hormone (TRH), have been identified previously in the male reproductive system. We report here that rat and human mammary gland contain neutral TRH-immunoreactive peptides which are not retained on cation or anion exchange chromatography and that similar peptides occur in the milk of rat, cow, ewe and sow. The TRH-like peptides in lyophilized milk from the cow were purified by gel exclusion chromatography, mini-column cation exchange chromatography and reversed phase high performance liquid chromatography (HPLC) and the chromatographed peptides were located by TRH radioimmunoassay (RIA). In each chromatographic system the major TRH-immunoreactive peptide from cow milk exhibited identical behavior to pGlu-Phe-Pro amide; in addition there were two minor TRH-immunoreactive components. The possible physiological role of the TRH-like peptides in the mammary gland is discussed. In a series of patients with breast carcinoma, mammary tumor tissue was shown to contain approximately four times more TRH-like peptide than normal mammary tissue from the same patient, raising the possibility that the TRH-like peptides may be implicated in tumor development.
authors.affiliation: Imperial College at St Mary's, London, UK.
authors.forename: M W
authors.initials: MW
authors.lastname: Ghilchik
authors.forename: M
authors.initials: M
authors.lastname: Tobaruela
authors.forename: J
authors.initials: J
authors.lastname: del Rio-Garcia
authors.forename: D G
authors.initials: DG
authors.lastname: Smyth
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000368:Aged; D000818:Animals; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008892:Milk / Q000378:metabolism*; D010455:Peptides / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012756:Sheep; D013552:Swine; D013973:Thyrotropin-Releasing Hormone / Q000032:analysis*
chemical_list: D010455:Peptides; D013973:Thyrotropin-Releasing Hormone