Journal of Applied Physiology, Vol 65, Issue 6 2552-2557, Copyright © 1988 by American Physiological Society

ARTICLES

Regulation of hepatic glucose production in running rats studied by glucose infusion

J. Vissing, B. Sonne and H. Galbo
Department of Medical Physiology B, Panum Institute, University of Copenhagen, Denmark.

The importance of metabolic feedback regulation vs. feedforward regulation of hepatic glucose production (HGP) during exercise was investigated in rats by infusing glucose intravenously from the onset of running. Glucose infusion equaled the average exercise-induced increase from basal to steady state in HGP found in saline-infused control rats. Rats were studied at two work loads, running at 21 (series I) or 18 m/min (series II) for 35 min. Glucose turnover was measured by means of an intravenous [3H]glucose infusion. HGP was suppressed by glucose infusion corresponding to the infused amount of glucose in both series, except for late in exercise in series I, where HGP plus infused glucose tended to exceed HGP in saline-infused rats (P less than 0.10). Muscle glycogenolysis and fat metabolism were similar in both groups in the two series. Plasma glucose was never elevated, whereas insulin was, in glucose- vs. saline-infused rats of both series. Plasma catecholamines were lower in glucose- compared with saline-infused rats in series II. In conclusion, HGP is very sensitive to metabolic feedback inhibition at low exercise intensities. Feedforward control of HGP may play a role at higher work loads (series I). Exogenously supplied glucose, in moderate amounts, may replace HGP specifically without concomitant changes in mobilization of other substrates.

This article has been cited by other articles:

				S. H. Kreisman, J. B. Halter, M. Vranic, and E. B. Marliss Combined Infusion of Epinephrine and Norepinephrine During Moderate Exercise Reproduces the Glucoregulatory Response of Intense Exercise Diabetes, June 1, 2003; 52(6): 1347 - 1354. [Abstract] [Full Text] [PDF]

				E. B. Marliss and M. Vranic Intense Exercise Has Unique Effects on Both Insulin Release and Its Roles in Glucoregulation: Implications for Diabetes Diabetes, February 1, 2002; 51(90001): S271 - 283. [Abstract] [Full Text] [PDF]

				S. H. Kreisman, A. Manzon, S. J. Nessim, J. A. Morais, R. Gougeon, S. J. Fisher, M. Vranic, and E. B. Marliss Glucoregulatory responses to intense exercise performed in the postprandial state Am J Physiol Endocrinol Metab, May 1, 2000; 278(5): E786 - E793. [Abstract] [Full Text] [PDF]

				S. H. Kreisman, N. A. Mew, M. Arsenault, S. J. Nessim, J. B. Halter, M. Vranic, and E. B. Marliss Epinephrine infusion during moderate intensity exercise increases glucose production and uptake Am J Physiol Endocrinol Metab, May 1, 2000; 278(5): E949 - E957. [Abstract] [Full Text] [PDF]

				A. Manzon, S. J. Fisher, J. A. Morais, L. Lipscombe, M.-C. Guimond, S. J. Nessim, R. J. Sigal, J. B. Halter, M. Vranic, and E. B. Marliss Glucose infusion partially attenuates glucose production and increases uptake during intense exercise J Appl Physiol, August 1, 1998; 85(2): 511 - 524. [Abstract] [Full Text] [PDF]

				K. Howlett, D. Angus, J. Proietto, and M. Hargreaves Effect of increased blood glucose availability on glucose kinetics during exercise J Appl Physiol, April 1, 1998; 84(4): 1413 - 1417. [Abstract] [Full Text] [PDF]