Metformin treatment enhances insulin-stimulated glucose transport in skeletal muscle of Sprague-Dawley rats.
Although the glucose-lowering properties of metformin are well-established, its effects on glucose metabolism in skeletal muscle have not been clearly defined. We tested the effects of metformin in young adult male Sprague-Dawley rats, which have a documented reduced response to insulin in skeletal muscle. Rats were treated with metformin for 20 days (320 mg/kg/day) in the drinking water. During this period, metformin completely prevented the increase in food intake and decreased adiposity by 30%. Metformin also reduced insulin secretion by 37% following an intra-peritoneal injection of glucose. Finally, metformin enhanced transport of [3H]-2-deoxyglucose in isolated strips of soleus muscle. Metformin substantially increased insulin-stimulated transport, while having no effect on basal transport. In control rats, a maximal concentration of insulin stimulated transport 77% above basal. In metformin-treated rats, insulin stimulated transport 206% above basal. We conclude that in the Sprague-Dawley rat model, metformin causes a significant increase in insulin-responsiveness.
Borst
S E
SE
Department of Pharmacology, University of Florida and Geriatric Research, Education and Clinical Center, VA Medical Center, Gainesville 32608-1197, USA. sborst@pharmacology.ufl.edu
Snellen
H G
HG
Lai
H L
HL
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004347:Drug Interactions; D004435:Eating / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008687:Metformin / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012741:Sexual Maturation
D007004:Hypoglycemic Agents; D007328:Insulin; D008687:Metformin; D005947:Glucose