Effect Of Acute Exercise On The Serum Concentrations Of Leptin, Glucose And Ralated Hormones In Human

Introduction
The discovery of the ob gene and its product, leptin(1), is rapidly changing our understanding of body fuels and opens the possibility for an entirely new approach for therapeutic interventions in obesity and its complications. Although leptin injection in rodents and exercise seem to attain the same physiological results (i.e. reduced appetite and increased energy expenditure), little is known about the relationship between them(2-7). In order to clear the topic further, we designed a research as follow

Methods
Twenty subjects were studied for the effect of 1-h exercise with increasing intensity on the level of leptin and its relationships with glucose, insulin, and growth hormone. Blood samples were drawn before, during and after the exercise. At the end, the intensity of exercise had reached middle to high.

Results
Serum GH and glucose were elevated after 30min exercise, and declined thereafter. Sex and BMI did not affect these concentration profiles. Though the changes in the leptin and insulin level profiles showed no or slight significance, the obese subjects did have significantly higher levels of both parameters than the leans subjects after 1-h exercise, an effect that was extended into the recovery period (P<0.05 or P<0.01). At these time points the correlations between BMI and insulin, and BMI and leptin were found to be improved greatly (P<0.05, P<0.01 and P<0.001), so was the relationship between leptin and insulin.

Discussion / Conclusion
The data have confirmed the close physiological relation between leptin and insulin; and the observation that significance changes occurred only at the end of 1-h exercise that reached high intensity instead of 30 min of moderate exercise suggests that the impact of exercise on leptin level might depend on its intensity and duration.

References
[1]. Zhang Y., Proenca R., Maffei M., Barone M., Leopold L., Friedman J. M.: Positional cloning of the mouse obese gene and its human homologue. Nature 372: 425-432, 1994.
[2]. Pérusse L., Collier G., Gagnon J., Leon A. S., Rao D. C., Skinner J. S., Wilmore J. H., Nadeau A., Zimmet P. Z., Bouchard, C.: Acute and chronic effects of xercise on leptin levels in humans. J Appl Physiol 83: 5-10, 1997.
[3]. Racette S. B., Coppack S. W., Landt M., Klein S.: Leptin production during moderate-intensity aerobic exercise. J Clin Endocrinol Metab 82: 2275-2277, 1997.
[4]. Saladin R. P. De Vos, Guerre-Millo M., Leturque A., Girard J., Staels B., Auwerx. J.: Transient increase in obese gene expression after food intake or insulin administration. Nature 377: 527-529, 1995.
[5]. Campfield L. A., Smith E. J., Guisez J., Devos R., Burn P.: Recombinant mouse OB protein evidence for a peripheral signal linking adiposity and central neural networks. Science 269: 546-549, 1995.
[6]. Dolkas C. B., Greenlead J. E.: Insulin and glucose responses during bed rest with isotonic and isometric exercise. J Appl Physiol 43: 1033-1038, 1977.
[7]. Hickey M. S., Considine R. V., Israel R. G., Mahar Y. L., McCammon M. R., Tyndall G. L., Houmard J. A., Caro J. F.: Leptin is related to body fat content in male distance runners. Am J Physiol 271: E938-E940, 1996.

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