Gonadotropin-releasing hormone-associated peptide immunoreactivity in bovine colostrum.
Gonadotropin-releasing hormone(GnRH)-associated peptide (GAP) is a 56-amino acid peptide found on the C-terminal of the GnRH (also called luteinizing hormone-releasing hormone) precursor and is assumed to be co-produced with GnRH. The purpose of this report is to demonstrate the presence of GAP immunoreactivity in bovine colostrum. Radioimmunoassay of acidified methanolic extracts demonstrated a concentration of GAP immunoreactivity of approximately 1.5 +/- 0.1 pmol/g dry skim bovine colostrum. Gel filtration (Sephadex G-10) and high-performance liquid chromatography of extracts containing GAP immunoreactivity showed it to be of low molecular weight and a high hydrophobic character. The presence of GAP immunoreactivity in bovine colostrum suggests that the GnRH precursor is synthesized and processed in mammary tissue itself.
Laboratory of Bioorganic Chemistry, School of Pharmaceutical Sciences, University of Shizyoka, Japan.
T
T
Zhang
K
K
Iguchi
T
T
Mochizuki
M
M
Hoshino
C
C
Yanaihara
N
N
Yanaihara
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003126:Colostrum / Q000032:analysis*; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis*; D008970:Molecular Weight; D011498:Protein Precursors / Q000032:analysis*; D011863:Radioimmunoassay
D011498:Protein Precursors; C050502:gonadotropin releasing hormone associated peptide; D007987:Gonadotropin-Releasing Hormone