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

• Published in: American journal of physiology: endocrinology and metabolism Vol. 280; no. 4; pp. E650 - E656
• Main Authors: Anthony, T. G, Anthony, J. C, Lewitt, M. S, Donovan, S. M, Layman, D. K
• Format: Journal Article
• Language: English
• Published: United States 01.04.2001
• Subjects: Animals; Blood Glucose - analysis; Eating - physiology; Insulin - blood; Insulin-Like Growth Factor Binding Protein 1 - blood; Insulin-Like Growth Factor Binding Protein 1 - metabolism; Insulin-Like Growth Factor I - analysis; Liver - metabolism; Male; Medicin och hälsovetenskap; Motor Activity - physiology; Rats; Rats, Sprague-Dawley; Time Factors
• ISSN: 0193-1849; 1522-1555
• DOI: 10.1152/ajpendo.2001.280.4.e650

1  Division of Nutritional Sciences and the Department of Food Science and Human Nutrition, University of Illinois, Urbana 61801; and 2  Unit for Endocrinology and Diabetes, Karolinska Institutet Department of Molecular Medicine, Karolinska Hospital L1:02, 171 - 76 Stockholm, Sweden 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-I, 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. insulin-like growth factor I; insulin-like growth factor binding protein-1; insulin