Metabolic mechanisms involved in the impaired insulin secretion in pancreatic islets isolated from exercised and fasted rats.
This study examined the metabolic mechanisms involved in the impaired insulin secretion by pancreatic islets isolated from fasted and exercised rats. Insulin secretion to glucose (8.3 to 16.7 mM) stimulus was lower in fasted (F), exercised (E), and fasted plus exercised (EF) rats as compared with the control group. The rate of glucose oxidation by isolated islets was reduced in F and EF rats, but it was not modified in the E group. In response to alpha-KIC (5, 10, 15, and 20 mM), insulin secretion was not different in EF and F rats, in comparison to controls, except in the E group, which showed values slightly higher. These findings suggest that changes in insulin secretion in fasted rats, associated or not to exercise training, might be a consequence of a reduced activity of the right-hand side of the Krebs cycle (from pyruvate to oxoglutarate), leading to decreased glucose oxidation. However, the exercise itself caused a significant decrease of insulin secretion without altering glycolysis and Krebs cycle activities.
Villela
F G
FG
Department of Physiology and Biophysics, University of São Paulo, Brazil.
Curi
R
R
Carpinelli
A R
AR
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002952:Citric Acid Cycle / Q000502:physiology; D046508:Culture Techniques; D004734:Energy Metabolism / Q000502:physiology*; D005215:Fasting / Q000502:physiology*; D007328:Insulin / Q000502:physiology*; D007515:Islets of Langerhans / Q000502:physiology*; D008297:Male; D010477:Perfusion; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012636:Secretory Rate / Q000502:physiology
D001786:Blood Glucose; D007328:Insulin