title: The TRH-like peptides in rabbit testis are different from the TRH-like peptide in the prostate.
abstract: Human seminal fluid contains a number of tripeptide amides with similar structures to thyrotropin releasing hormone (TRH), two of which have been identified as pGlu-Glu-Pro amide and pGlu-Phe-Pro amide. To determine whether these peptides originate in the same tissues and have the same molecular origin, TRH-immunoreactive peptides were extracted from the prostate and testis of the rabbit, purified by ion exchange chromatography and HPLC, and identified by co-chromatography with 3H-labelled marker peptides. In addition, trypsin digestion was used to release TRH-like tripeptides from N-extended forms of these peptides. The sole TRH-like peptide in the prostate was shown to be pGlu-Glu-Pro amide; it was not accompanied by a detectable amount of pGlu-Phe-Pro amide. The prostate also appeared to contain a very small amount of N-extended forms of these peptides. In contrast to the prostate, the testis contained high concentrations of N-extended forms of pGlu-Phe-Pro amide but essentially no tripeptide. The testis also contained N-extended forms of two other neutral TRH-like peptides which were less hydrophobic than pGlu-Phe-Pro amide. Neither the prostate nor the testis contained a significant amount of TRH. The results show that in the rabbit the TRH-like peptides pGlu-Glu-Pro amide and pGlu-Phe-Pro amide occur in different tissues and appear to be formed from different precursors.
authors.affiliation: National Institute for Medical Research, Mill Hill, London, UK.
authors.forename: H
authors.initials: H
authors.lastname: Linden
authors.forename: J
authors.initials: J
authors.lastname: del Rio Garcia
authors.forename: A
authors.initials: A
authors.lastname: Huber
authors.forename: G
authors.initials: G
authors.lastname: Kreil
authors.forename: D
authors.initials: D
authors.lastname: Smyth
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry* / Q000302:isolation & purification; D011467:Prostate / Q000737:chemistry*; D011498:Protein Precursors / Q000737:chemistry / Q000302:isolation & purification; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011817:Rabbits; D012661:Semen / Q000737:chemistry; D013737:Testis / Q000737:chemistry*; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D014018:Tissue Distribution
chemical_list: D009842:Oligopeptides; D011498:Protein Precursors; C074033:pyroglutamyl-phenylalanyl-prolinamide; D013973:Thyrotropin-Releasing Hormone; C059697:pyroglutamyl-glutamyl-proline amide; D011761:Pyrrolidonecarboxylic Acid