Abstract
Using specific radioimmunoassays, we studied the occurrence of amidated and glycine-extended glucagon-like peptide I (GLP-I) molecules in the human small intestine and pancreas and in the circulation system in response to a breakfast meal. Through gel permeation chromatography of extracts of the human pancreas (n = 5), we found that 71% of the GLP-I immunoreactivity eluted as a large molecule corresponding to the major proglucagon fragment, 24% corresponded to GLP-I 1-36 amide, and 5% to GLP-I 1-37. By gel permeation chromatography of extracts of human small intestine (n = 6), we found that all immunoreactivity eluted in one peak at the common elution position of the two insulin-releasing peptides, GLP-I 7-36 amide and GLP-I 7-37. Of the GLP-I immunoreactivity, 80% corresponded to GLP-I 7-36 amide and 20% to GLP-I 7-37. The mean concentrations of amidated GLP-I and glycine-extended GLP-I in fasting plasma were 7 +/- 1 and 6 +/- 1 pM, respectively (n = 6). In response to a breakfast meal, the concentration of amidated GLP-I rose significantly amounting to 41 +/- 5 pM 90 min after the meal ingestion, whereas the concentration of glycine-extended GLP-I only rose slightly to a maximum of 10 +/- 1 pM. Thus, both amidated and glycine-extended GLP-I molecules are produced in the small intestine and in the pancreas in humans. Both amidated and glycine-extended GLP-I are measurable in fasting plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
| Original language | English |
|---|---|
| Journal | Diabetes |
| Volume | 43 |
| Issue number | 4 |
| Pages (from-to) | 535-9 |
| Number of pages | 5 |
| ISSN | 0012-1797 |
| Publication status | Published - Apr 1994 |
Keywords
- Adult
- Chromatography, Gel
- Eating
- Fasting
- Female
- Glucagon
- Glucagon-Like Peptide 1
- Humans
- Immunohistochemistry
- Intestine, Small
- Male
- Middle Aged
- Pancreas
- Peptide Fragments
- Proglucagon
- Protein Precursors
- Protein Processing, Post-Translational