title: Measurement of bovine somatotropin (bST) and insulin-like growth factor-1 (IGF-1) in bovine milk using an electrochemiluminescent assay.
abstract: Bovine somatotropin (bST) and insulin-like growth factor-1 (IGF-1) are peptide hormones that are involved in the regulation of milk production in dairy cows. Because these hormones are present at extremely low concentration in fresh and processed bovine milk, a highly sensitive and specific electrochemiluminescent immunoassay (ECLIA) has been developed to better estimate the concentration of these hormones in milk. The assay employs an imager, a capture antibody bound to a carbon electrode, and a detection antibody coupled to a ruthenium label. In the presence of tripropylamine and an electric pulse, ruthenium generates light proportional to the amount of antigen bound, and the light is captured as signal by a charge-coupled device (CCD) camera. Using bovine milk as the starting matrix, 99.69% of bST and 104.79% of IGF-1 were recoverable. The limit of detection (LOD) was <5 pg/mL for bST and <1 pg/mL for IGF-1. The limit of quantification (LOQ) was <14 pg/mL for bST in milk and <2 pg/mL of IGF-1. The assay is highly specific and shows <0.2% cross-reactivity with other peptide hormones found in bovine milk such as insulin and IGF-2. These data indicate this new, ECLIA is highly sensitive and specific for estimating the concentration of bST or IGF-1 in milk.
authors.affiliation: Monsanto Company, 800 North Lindbergh Boulevard, St. Louis, Missouri 63167, USA. Michael.f.mcgrath@monsanto.com
authors.forename: Michael F
authors.initials: MF
authors.lastname: McGrath
authors.forename: Gregg
authors.initials: G
authors.lastname: Bogosian
authors.forename: Anabella C
authors.initials: AC
authors.lastname: Fabellar
authors.forename: Robin L
authors.initials: RL
authors.lastname: Staub
authors.forename: John L
authors.initials: JL
authors.lastname: Vicini
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Widger
mesh_terms: D000818:Animals; D002417:Cattle; D004563:Electrochemistry; D005511:Food Handling; D013006:Growth Hormone / Q000032:analysis*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008163:Luminescent Measurements / Q000379:methods*; D008892:Milk / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: C073294:growth hormone, bovine; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone