Insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBP) during 24 hours after injection of equine growth hormone (eGH) in mares

S. V. Radecki, R. A. Christensen, K. Malinowski, C. G. Scanes

Research output: Contribution to journalArticlepeer-review

Abstract

Mares aged 18 to 25 yr were given daily sc injections of eGH (0, 6.25 or 12.5 mg; n = 5 or 6) for 43 days. On days 1 and 43, blood was sampled at 0, .25, .5,1,2,4, 8, and 24 h after eGH. Blood plasma eGH and IGF-1 were determined by RIA. Plasma proteins were separated by SDS-PAGE, and IGFBP were quantified by densitometry of ligand blots on PVDF membranes. Plasma GH increased (P &lt; .05) 550 and 371% at 2 hr after 6.25 mg eGH injection on days 1 and 43, respectively; and 384 and 650% after 12.5 mg eGH, respectively. Plasma IGF-I increased (133%, P < .05) by 24 hr alter eGH on day 1, but not on day 43. However, IGF-I on day 43 averaged 275% (P < .05) of day 1. Six IGFBP (26,39,46, 48, 97 and 107 kDa) were identified. The 26, 46, 48 and 97 kDa IGFBP increased (P < .05) about four-fold after 43 days of 6.25 mg daily eGH, but the 26 and 39 kDa IGFBP were reduced (P < .05) after 43 days of 12.5 mg eGH. Both doses increased (P < .05) the 107 kDa 1GF-T3P after 43 days. We conclude that the IGF-I axis is responsive to exogenous eGH in aged mares. (Supported by the NJ Equine Research Initiative and Bresatec Ltd., Adelaide, Australia.).

Original languageEnglish (US)
Pages (from-to)A769
JournalFASEB Journal
Volume10
Issue number3
StatePublished - 1996

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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