Evaluation of serum insulin-like growth factor binding proteins (IGFBP) in Angus cattle divergently selected for serum IGF-I concentration.

Abstract

Postweaning serum insulin-like growth factor-I (IGF-I) concentrations and serum IGF binding proteins (IGFBP) were investigated in 68 (1992 Fall-born) and 84 (1999 Fall-born) Angus cattle selected for either high or low serum IGF-I concentrations since 1989. Relative serum levels of IGFBP were determined by [125I]IGF-I Western ligand blotting. IGFBP species of 38-42, 34, 30, and 24 kDa were identified. The 34 kDa species was identified as IGFBP-2 by immunoblot analysis. No significant line effects were observed for any of the IGFBP. In both 1992 and 1999, heifers had higher IGFBP-2 levels than bulls (P<0.0005). In 1992 calves, relative levels of the 38-42 and 24 kDa species were significantly correlated with serum IGF-I concentration. In 1999 calves, none of the IGFBP were correlated with serum IGF-I, although IGFBP-2 was negatively correlated with several measures of body weight. No significant line effects were observed for growth or serum IGF-I traits in 1992 calves. However, 1999 high line calves had higher serum IGF-I concentrations and body weights than low line calves (P<0.05). In both 1992 and 1999 calves, bulls had higher serum IGF-I concentrations and body weights than heifers (P<0.05). Thus, while selection for high versus low serum IGF-I concentrations has resulted in divergence between the selection lines and also in changes in body weights, it has not resulted in changes in serum IGFBP levels. Furthermore, circulating IGFBP-2 appears to be higher in heifers than in bulls, and also appears to be negatively correlated with body weights.

• Authors: M Pagan, M E Davis, D A Stick, R C M Simmen, N E Raney, R J Tempelman, C W Ernst
• Journal: Domestic animal endocrinology (Domest Anim Endocrinol) Vol. 25 Issue 4 Pg. 345-58 (Nov 2003) ISSN: 0739-7240 [Print] United States
• PMID: 14652135 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Insulin-Like Growth Factor Binding Protein 2
• Insulin-Like Growth Factor Binding Proteins
• Iodine Radioisotopes
• Insulin-Like Growth Factor I

Topics

• Animals
• Biometry
• Blotting, Western
• Body Weight
• Cattle (anatomy & histology, blood, genetics)
• Female
• Insulin-Like Growth Factor Binding Protein 2 (blood)
• Insulin-Like Growth Factor Binding Proteins (blood)
• Insulin-Like Growth Factor I (analysis)
• Iodine Radioisotopes
• Male
• Selection, Genetic
• Sex Characteristics
• Weaning
• Weight Gain