title: Validation of the IDS Octeia ELISA for the determination of insulin-like growth factor 1 in equine serum and tendon tissue extracts.
abstract: BACKGROUND
  Insulin-like growth factor (IGF-1) is an important mediator of tissue repair in horses.
  
  
  OBJECTIVE
  The aim of the study was to evaluate whether IGF-1 could be measured reliably in equine serum and tendon tissue extracts, using an IGF-1 ELISA kit developed for human serum and plasma.
  
  
  METHODS
  A glycyl-glycine pretreatment protocol of samples was compared with the pretreatment procedure recommended by the manufacturer. Intra- and inter-assay imprecision were evaluated by repeated measurements of equine serum pools. Assay inaccuracy was determined based on the linearity of serially diluted equine serum samples and tendon tissue extracts. The recovery of IGF-1 was evaluated in serum and tendon tissue extracts spiked with known amounts of IGF-1.
  
  
  RESULTS
  The range of IGF-1 released using the manufacturer's pretreatment was between 23% and 56% of the amount released using the gly-gly pretreatment in different equine samples. In serum pools with low, intermediate, and high IGF-1 concentrations, intra-assay imprecision was 4.0%, 4.0%, and 3.1%, respectively, and inter-assay imprecision was 13.9%, 7.3%, and 12.8%, respectively. The recovery of serially diluted serum was 96 ± 3% when diluted with serum, and 72 ± 15% when diluted with PBS. The recovery after dilution was 108 ± 17% in tendon tissue extracts. Recovery from serum spiked with a fixed amount of IGF-1 was 101 ± 5% and 99 ± 7% from tendon tissue samples.
  
  
  CONCLUSIONS
  The IDS Octeia IGF-1 ELISA kit can be used for measuring IGF-1 in equine serum and tendon tissue extract after pretreatment with glycyl-glycine.
authors: Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark.
authors: Tone
authors: T
authors: Lygren
authors: Peter
authors: P
authors: Schjerling
authors: Stine
authors: S
authors: Jacobsen
authors: Lise C
authors: LC
authors: Berg
authors: Mette O
authors: MO
authors: Nielsen
authors: Henning
authors: H
authors: Langberg
authors: Preben D
authors: PD
authors: Thomsen
mesh_terms: D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary*; D006736:Horses / Q000097:blood / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000378:metabolism; D011485:Protein Binding; D011933:Reagent Kits, Diagnostic / Q000662:veterinary*; D015203:Reproducibility of Results; D013710:Tendons / Q000737:chemistry / Q000378:metabolism*; D014020:Tissue Extracts / Q000737:chemistry / Q000378:metabolism
chemical_list: D011933:Reagent Kits, Diagnostic; D014020:Tissue Extracts; D007334:Insulin-Like Growth Factor I