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Muscle insulin-like growth factor-I (IGF-I) receptors in chickens with high or low body weight: effects of age and muscle fibre type.

Authors
  • Oudin, A1
  • Chevalier, B
  • Simon, J
  • Duclos, M J
  • 1 Institut National de la Recherche Agronomique, Station de Recherches Avicoles, Endocrinologie de la Croissance et du Métabolisme, Nouzilly, France. , (France)
Type
Published Article
Journal
Growth Hormone & IGF Research
Publisher
Elsevier
Publication Date
Jun 01, 1998
Volume
8
Issue
3
Pages
243–250
Identifiers
PMID: 10984313
Source
Medline
License
Unknown

Abstract

IGF-I receptors were characterized in leg and breast muscles from 1- and 7-week-old chickens selected for high (HG) or low (LG) growth rate. Following whole muscle solubilization, receptors were partially purified by wheat germ agglutinin (WGA) chromatography. IGF-I and insulin binding did not differ between genotypes, but significantly decreased with age, without any change in receptor affinity. In the older birds, insulin binding was lower in breast than in leg muscle, whereas IGF-I binding was similar. Using the artificial substrate poly(Glu-Tyr) 4:1, the IGF-I-stimulated tyrosine kinase activity of the receptors was measured and compared between genotypes (at 1 week), and in HG chickens between muscle types (1 and 7 weeks) and ages (in leg muscle). It was not modified by any of these factors. We conclude that: (1) IGF-I and insulin receptor number do not differ between genotypes, (2) the number of both receptors decreases with age, and (3) in 7-week-old birds, breast muscle could become less responsive to insulin than leg muscles, following a decrease in receptor number.

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