Abstract
Phenformin at high doses (10 mg/1, 50 mg/1, and 100 mg/1) increased the insulin and
lactate output rates by the isolated perfused rat pancreas. Glucagon secretion was
not modified. There was a statistically significant correlation between the increase
in insulin and lactate output rates induced by phenformin. Intra-pancreatic L (+)
lactate concentrations induced by phenformin were in the range of sodium L (+) lactate
concentrations which experimentally stimulated insulin secretion by the same preparation.
Thiamin pyrophosphate and sodium dichloroacetate, which promote the aerobic metabolism
of pyruvate, opposed the phenformin induced increase in lactate output by the isolated
perfused rat pancreas and provoked as well a decrease in insulin release.
These results suggest that the increase in insulin secretion following the administration
of phenformin at high concentrations can be explained, to a large extent, by the increase
in the production of lactate ions.
Key words
Phenformin - Lactate - In-vitro Insulin Secretion - Thiamine Pyrophosphate - Sodium
Dichloroacetate - Isolated Perfused Pancreas
