Abstract
BACKGROUND: The insulinotropic hormones gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), secreted from the K-cells of the upper small intestine and from the L-cells of the lower small intestine, respectively, are thought to be responsible for intestinal stimulation of insulin secretion. If true, their plasma concentrations should parallel the meal-related diurnal changes in plasma insulin concentrations.
METHODS: Using COOH-terminal assays, thought to reflect accurately their rates of secretion, we measured circulating levels of GIP and GLP-1 in six normal subjects for 15 h of a day, during which they ate three mixed meals.
RESULTS: Both GIP and GLP-1 concentrations increased significantly and in parallel with insulin in response to all three meals. The plasma insulin concentrations correlated significantly with both GIP and GLP-1 values throughout the study period (correlation coefficients, 0.49 +/- 0.07 and 0.56 +/- 0.05; p < 0.001).
CONCLUSIONS: These results support the notion that GLP-1 and GIP are important incretin hormones.
| Original language | English |
|---|---|
| Book series | Scandinavian Journal of Gastroenterology |
| Volume | 31 |
| Issue number | 7 |
| Pages (from-to) | 665-70 |
| Number of pages | 6 |
| ISSN | 0036-5521 |
| DOIs | |
| Publication status | Published - Jul 1996 |
Keywords
- Adult
- Circadian Rhythm
- Female
- Gastric Inhibitory Polypeptide/secretion
- Gastrointestinal Hormones/secretion
- Glucagon/secretion
- Glucagon-Like Peptide 1
- Glucagon-Like Peptides
- Humans
- Insulin/secretion
- Intestine, Small/secretion
- Male
- Peptide Fragments/secretion