title: Blood plasma concentrations of insulin-like growth factor-I (IGF-I) in resting standardbred horses.
abstract: A survey of standardbred horses was conducted to build up a normal population profile for insulin like growth factor-I (IGF-I) concentrations in racing standardbreds and to ascertain how age, sex and geographic location affect IGF-I. Blood samples were drawn by jugular venepuncture from 202 racing standardbred horses aged one to eight years located in five different geographic regions of New Zealand. IGF-I concentrations were determined by insulin like growth factor-I binding protein (IGFBP)-blocked radioimmunoassay validated for the horse. As described in other species, age played a significant (P<0.05) role in IGF-I concentrations with the highest concentrations occurring in the younger horses. There was a significant (P<0.05) sex effect, intact males having significantly higher IGF-I concentrations compared of mares and/or geldings. Geographic location had a significant (P<0.05) influence on IGF-I. A significant (P<0.05) trainer effect also was noted both within and between geographic locations. We concluded that IGF-I concentrations in racing standardbred horses are affected by age, sex, trainer and geographic location.
authors.affiliation: Research Centre in Reproductive Medicine, The University of Auckland, Private Bag, Auckland, New Zealand. z.champion@auckland.ac.nz
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Champion
authors.forename: B H
authors.initials: BH
authors.lastname: Breier
authors.forename: W E
authors.initials: WE
authors.lastname: Ewen
authors.forename: T T
authors.initials: TT
authors.lastname: Tobin
authors.forename: P J
authors.initials: PJ
authors.lastname: Casey
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D006736:Horses / Q000097:blood*; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000378:metabolism; D007601:Jugular Veins; D008297:Male; D009520:New Zealand; D011863:Radioimmunoassay / Q000662:veterinary; D012016:Reference Values; D012737:Sex Factors
chemical_list: D018970:Insulin-Like Growth Factor Binding Protein 1; D007334:Insulin-Like Growth Factor I