Insulin secretion in monosodium glutamate (MSG) obese rats submitted to aerobic exercise training.
The present study was designed to evaluate the effects of aerobic exercise training on glucose tolerance and insulin secretion of obese male Wistar rats (monosodium glutamate [MSG] administration, 4 mg/g-body weight, each other day, from birth to the 14th day). Fourteen weeks after the drug administration, the rats were separated into two groups: MSG-S (sedentary) and MSG-T (T = swimming, 1 h/day, 5 days/week, with an overload of 5% body weight for 10 weeks). Rats of the same age and strain injected with saline were used as control (C) and subdivided into two groups: C-S and C-T. Insulin and glucose responses during an oral glucose tolerance test (GTT) were evaluated by the estimation of the total areas under serum insulin (AI) and glucose (AG) curves. Glucose-induced insulin secretion by isolated pancreatic islets was also evaluated. MSG-S rats showed higher AI than C-rats while MSG-T rats presented lower AI than MSG-S rats. No differences in AG were observed among the 4 groups. Pancreatic islets from MSG-rats showed higher insulin secretion in response to low (2.8) and moderate (8.3 mM) concentrations of glucose than those from their control counterparts and no differences were observed between MSG-S and MSG-T rats. These results provide evidences that the hyperinsulinemia at low or moderate glucose concentrations observed in MSG-obese rats is, at least in part, a consequence of direct hypersecretion of the B cells and that chronic aerobic exercise is able to partially counteract the hyperinsulinemic state of these animals without disrupting glucose homeostasis.
de Souza
Claudio Teodoro
CT
Departamento de Educação Física, Instituto de Biociências, Universidade Estadual Paulista (UNESP), 13506-900 Rio Claro, SP, Brazil.
Nunes
Wilton Marlindo Santana
WM
Gobatto
Claudio Alexandre
CA
de Mello
Maria Alice Rostom
MA
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D005223:Fats / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000494:pharmacology; D005951:Glucose Tolerance Test; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D019344:Lactic Acid / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood / Q000139:chemically induced / Q000378:metabolism* / Q000628:therapy*; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012970:Sodium Glutamate / Q000008:administration & dosage / Q000494:pharmacology*
D001786:Blood Glucose; D005223:Fats; D007328:Insulin; D019344:Lactic Acid; D005947:Glucose; D012970:Sodium Glutamate