Effect of marathon run on serum IGF-I and IGF-binding protein 1 and 3 levels.

Full Abstract

Acute physical exercise increases growth hormone (GH) secretion, and GH regulates the expression of insulin-like growth factor I (IGF-I) and IGF-binding protein (IGFBP) 3. IGFBP-1 is a local modulator of IGF activity with rapid dynamic regulation that is downregulated by insulin. The IGF system mediates the metabolic actions of GH, and possibly it regulates glucose metabolism. We hypothesize that strenuous exercise causes changes in the IGF system. We studied the effects of the marathon run on the circulating levels of IGF-I, IGFBP-1, IGFBP-3, and insulin in 23 participants. Immediately after the run, the most striking change was an 11.6-fold median increase in serum IGFBP-1 level (from 63.7 +/- 50.5 to 736 +/- 408 micrograms/l; P < 0.001). Because the insulin level remained unchanged, the elevation of serum IGFBP-1 level cannot be explained by changes in insulin. One day after the run, the IGFBP-1 level had returned to baseline. The physiological role of this increment could be the inhibition of hypoglycemic effects of IGF-I and/or regulation of glucose availability to the muscles. The changes in IGF-I and IGFBP-3 levels were less dramatic: the IGF-I and IGFBP-3 levels were lower 1 and 3 days after the run. This report provides an important basis for authentic effects of strenuous exercise on the IGF-system.

Author information

Author/s: Koistinen, H (H); Koistinen, R (R); Selenius, L (L); Ylikorkala, Q (Q); Seppälä, M (M);

Affiliation: Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Finland.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Journal of applied physiology (Bethesda, Md. : 1985) (J Appl Physiol), published in UNITED STATES. (Language: eng)

Reference: 1996-Mar; vol 80 (issue 3) : pp 760-4

Dates: Created 1996/12/03; Completed 1996/12/03; Revised 2006/11/15;

PMID: 8964734, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article
(including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.