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Horm Metab Res 1971; 3(6): 366-373
DOI: 10.1055/s-0028-1094123
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© Georg Thieme Verlag KG Stuttgart · New York

Labelled Insulin Catabolism and Pancreatic Responsiveness During Long-Term Exercise in Man[*]

J. R.M. Franckson , R.  Vanroux , R.  Leclercq , H.  Brunengraber , H. A. Ooms
  • Service de Chimie Médicale, Hôpital Saint-Pierre Bruxelles et Centre de Physiopathologie Respiratoire, Hôpital civil de Charleroi, Université Libre de Bruxelles
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Publication History

Publication Date:
08 January 2009 (online)

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Abstract

Most studies concerning the influence of exercise on insulin secretion, only dealt with the level of plasma IRI. Our aim was to measure both insulin catabolism and pancreatic responsiveness.

Muscular exercise (bicycle ergometer, Power 80 W, workload 40% of max VO2), maintained in steady state of ventilation during 40 min, was performed by several groups of normal subjects. The following results were obtained.
(1) In normoglycemia or in hyperglycemia caused by glucose infusion, exercise induced no decrease in plasma IRI level (2) The metabolic clearance rate of a constant infusion of 125I-insulin (0.2 atom I/mol) showed a reduction averaging 17% whereas no change in extracellular space could be detected. This decrease in insulin catabolism was associated with a similar decrease in the clearance rates of labelled hippuran and BSP. (3) Insulin response to glucagon injection was markedly reduced. (4) Plasma norepinephrine levels were increased.

In conclusion, the absence of change in plasma IRI level often described in non strenuous exercise results from the balance of two antagonistic phenomena: a decreased secretion rate probably related to the release of endogenous catecholamines and a decreased catabolic rate, apparently due to changes in liver and kidney haemodynamics.

Key words

Exercise - Plasma Glucose - Plasma Insulin - Labelled Insulin Catabolism - Response to Glucagon - BSP - Hippuran - Catecholamines

1 Work partially realized unter contract of the Ministère de la Politique Scientifique within the framework of the association Euratom-University of Brussels - Universitiy of Pisa and partially supported by grant nr 1014 (Fonds de la Recherche Scientifique Médicale)

1 Work partially realized unter contract of the Ministère de la Politique Scientifique within the framework of the association Euratom-University of Brussels - Universitiy of Pisa and partially supported by grant nr 1014 (Fonds de la Recherche Scientifique Médicale)

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