Abstract
The aim of the study was to investigate the effects of a dipeptidyl peptidase-4 (DPP-4) inhibitor, of metformin, and of the combination of the two agents, on incretin hormone concentrations. Active and inactive (or total) incretin plasma concentrations, plasma DPP-4 activity, and preproglucagon (GCG) gene expression were determined after administration of each agent alone or in combination to mice with diet-induced obesity (DIO) and to healthy human subjects. In mice, metformin increased Gcg expression in the large intestine and elevated the plasma concentrations of inactive glucagon-like peptide 1 (GLP-1) (9-36) and glucagon. In healthy subjects, a DPP-4 inhibitor elevated both active GLP-1 and glucose dependent insulinotropic polypeptide (GIP), metformin increased total GLP-1 (but not GIP), and the combination resulted in additive increases in active GLP-1 plasma concentrations. Metformin did not inhibit plasma DPP-4 activity either in vitro or in vivo. The study results show that metformin is not a DPP-4 inhibitor but rather enhances precursor GCG expression in the large intestine, resulting in increased total GLP-1 concentrations. DPP-4 inhibitors and metformin have complementary mechanisms of action and additive effects with respect to increasing the concentrations of active GLP-1 in plasma.
Original language | English |
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Journal | Clinical Pharmacology and Therapeutics |
Volume | 88 |
Issue number | 6 |
Pages (from-to) | 801-8 |
Number of pages | 8 |
ISSN | 0009-9236 |
DOIs | |
Publication status | Published - 1 Dec 2010 |
Keywords
- Adolescent
- Adult
- Animals
- Cross-Over Studies
- Dipeptidyl-Peptidase IV Inhibitors
- Double-Blind Method
- Drug Therapy, Combination
- Female
- Glucagon-Like Peptide 1
- Humans
- Male
- Metformin
- Mice
- Mice, Inbred C57BL
- Middle Aged
- Obesity
- Young Adult