Changes in insulin response to glucose after exercise training in partially pancreatectomized rats.
The effects of exercise training on glucose-stimulated insulin secretion (GSIS) were studied in male Sprague-Dawley rats made mildly to severely diabetic by partial pancreatectomy. Exercise trained (10 wk treadmill; T) and untrained (Unt) rats were grouped according to posttraining fed-state hyperglycemia as follows: T less than 200 and Unt less than 200 (glucose concn less than 200 mg/dl), T 200-300 and Unt 200-300 (glucose concn 200-300 mg/dl), and T greater than 300 and Unt greater than 300 (glucose concn greater than 300 mg/dl). After exercise training, hyperglycemic glucose clamps were performed in awake rats by elevation of arterial blood glucose concentration 126 mg/dl above fasting basal levels for 90 min. Exercise training significantly increased muscle citrate synthase activity. Prevailing hyperglycemia was reduced during the 10-wk exercise training period in all T rats with fed-state glucose concentrations less than 300, and only 53% of Unt rats in these groups had reduced glycemia. GSIS was significantly higher in T less than 200 [2.4 +/- 0.7 (SD) ng/ml at 90 min] than in Unt less than 200 (1.5 +/- 0.3). A similar response was found for T 200-300 (1.1 +/- 0.3 ng/dl) vs. Unt 200-300 (0.7 +/- 0.1) but not T greater than 300 (0.36 +/- 0.2) vs Unt greater than 300 (0.44 +/- 0.05). Sham-operated control rats had insulin concentrations of 6.6 +/- 1.6 ng/ml at the 90th min of the clamp. Acute exercise reduced fed-state glycemia in rats with mild-to-moderate (less than 300 mg/dl) diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)
Farrell
P A
PA
Laboratory for Human Performance Research, Pennsylvania State University, University Park 16802.
Caston
A L
AL
Rodd
D
D
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology; D005947:Glucose / Q000008:administration & dosage*; D006943:Hyperglycemia / Q000503:physiopathology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000502:physiology*; D008297:Male; D010180:Pancreatectomy; D010805:Physical Conditioning, Animal; D005082:Physical Exertion / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D005947:Glucose