The effect of physical training on glucose, insulin, and glucagon response to epinephrine was assessed in normal and diabetic rats. Male Wistar rats were injected with streptozocin (STZ, 45 mg/kg) and those presenting 1 wk later a blood glucose value between 250 and 400 mg/dl were retained in the protocol and randomly assigned to a sedentary or trained group. Similar studies were conducted in control animals. Physical training was done on a treadmill according to a 10-wk program. Epinephrine (0.75 fxg/kg/min) was infused intravenously (i.v.) in previously cannulated rats for 1h and arterial blood samples obtained at 15-min intervals for glucose, insulin, and glucagon measurements. Pancreatic insulin and glucagon content was also determined. Basal glucose levels were significantly lower in trained than in sedentary diabetic rats (P < 0.01). The hyperglycemic response to epinephrine was diminished by 19% and 23% in trained control and diabetic animals, respectively, with a faster return to baseline after stopping epinephrine infusion in both trained groups. Although in nondiabetic rats thjs could be related to some diminution in the suppressive effect of epinephrine on insulin secretion, this was not the case in diabetic animals. Moreover, while training did not modify epinephrine-induced glucagon response in control rats, the twofold greater (P < 0.01) glucagon response observed in sedentary diabetic rats was restored to normal in trained diabetic rats. After stopping epinephrine infusion, glucagon levels dropped below the baseline in both groups of trained rats but not in their sedentary counterparts. These effects of training on glucagon response could not be explained by changes in pancreatic glucagon content. These findings suggest that physical training modulates the pancreatic alpha cell response to adrenergic stimulation and/or glucose plus insulin suppression. Diminution in glucagon secretion may thus possibly contribute to the training-induced improvement in the glucose homeostasis of STZ-diabetic rats.
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Original Contributions|
December 01 1985
Diminished Glucagon Response to Epinephrine in Physically Trained Diabetic Rats
A Nadeau;
A Nadeau
Laboratoire de Recherches en Endocrinologie et Métabolisme, Le Centre Hospitalier de I'Université Laval
Ste.-Foy, Québec, Canada
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S Rousseau-Migneron;
S Rousseau-Migneron
Laboratoire de Recherches en Endocrinologie et Métabolisme, Le Centre Hospitalier de I'Université Laval
Ste.-Foy, Québec, Canada
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G Tancrède;
G Tancrède
Laboratoire de Recherches en Endocrinologie et Métabolisme, Le Centre Hospitalier de I'Université Laval
Ste.-Foy, Québec, Canada
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C Jobidon;
C Jobidon
Laboratoire de Recherches en Endocrinologie et Métabolisme, Le Centre Hospitalier de I'Université Laval
Ste.-Foy, Québec, Canada
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D Trudel
D Trudel
Laboratoire de Recherches en Endocrinologie et Métabolisme, Le Centre Hospitalier de I'Université Laval
Ste.-Foy, Québec, Canada
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Address reprint requests to André Nadeau, M.D., F.R.C.P.(C), Le Centre Hospitalier de I'Université Laval, 2705 Boul. Laurier, Ste.-Foy, Québec, G1V 4G2 Canada.
Diabetes 1985;34(12):1278–1282
Article history
Received:
November 26 1984
Revision Received:
June 11 1985
PubMed:
3905462
Citation
A Nadeau, S Rousseau-Migneron, G Tancrède, C Jobidon, D Trudel; Diminished Glucagon Response to Epinephrine in Physically Trained Diabetic Rats. Diabetes 1 December 1985; 34 (12): 1278–1282. https://doi.org/10.2337/diab.34.12.1278
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