Plasma glucagon suppression by phenformin in man

Area of Science:

• Endocrinology
• Pharmacology

Background:

• Juvenile-onset diabetes mellitus requires insulin therapy.
• Phenformin is an oral antihyperglycemic agent.

Purpose of the Study:

• To elucidate the mechanism of action of phenformin in juvenile-onset insulin-requiring diabetics.
• To assess phenformin's effect on postprandial hyperglycemia and related hormonal responses.

Main Methods:

• Four treatment regimens were tested in eleven subjects: control, insulin alone, phenformin alone, and phenformin plus insulin.
• Standard breakfast tests were conducted to measure glucose, glucagon, triglyceride, gastrin, and growth hormone levels.

Main Results:

• Phenformin significantly decreased postprandial hyperglycemia compared to control.
• Phenformin combined with insulin further reduced postprandial glucose rise more than insulin alone.
• Phenformin reduced early postprandial hyperglucagonemia without affecting triglyceride, gastrin, or growth hormone levels.

Conclusions:

• Phenformin effectively lowers postprandial hyperglycemia in this diabetic population.
• Suppression of postprandial hyperglucagonemia is a potential mechanism for phenformin's antihyperglycemic action.