Time course changes in IGFBP-1 after treadmill exercise and postexercise food intake in rats

T. G. Anthony, J. C. Anthony, M. S. Lewitt, S. M. Donovan, D. K. Layman

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Abstract

Prolonged exercise increases circulating insulin-like growth factor binding protein-1 (IGFBP-1) in humans and animals, but its physiological significance is unknown. This study examined 1) time-course changes in plasma IGFBP-1 and hepatic IGFBP-1 mRNA expression after exercise, 2) changes in IGFBP-1 in relation to plasma glucose, insulin, and IGF-1, and 3) the impact of feeding a postexercise meal on the IGFBP-1 response. Food-deprived male rats were vigorously run on a treadmill and compared with nonexercised controls at 15 min and 1, 4, 8, and 12 h after exercise. Circulating insulin concentrations in exercised rats were lower than in controls at 15 min and 1 h, whereas plasma glucose and IGF-I remained unaffected. Circulating and hepatic expression of IGFBP-1 was markedly increased above that of controls at 15 min, 1 h, and 12 h. In a separate experiment, one-half of the exercised animals received a nutritionally complete meal immediately after the experimental run. The meal elevated plasma insulin and glucose concentrations at 15 min and 1 h. Despite this change in nutritional status, serum IGFBP-1 concentrations and hepatic IGFBP-1 abundance remained elevated at 15 min and 1 h. These results demonstrate that the IGFBP-1 response to a single bout of treadmill exercise is short in duration and independent of insulin, glucose, and amino acid availability.

Original languageEnglish (US)
Pages (from-to)E650-E656
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume280
Issue number4 43-4
StatePublished - Apr 1 2001
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

Keywords

  • Insulin
  • Insulin-like growth factor I
  • Insulin-like growth factor binding protein-1

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