No correlation between insulin and islet amyloid polypeptide after stimulation with glucagon-like peptide-1 in type 2 diabetes.
OBJECTIVE
To examine whether glucagon-like peptide-1 (GLP-1), which has been suggested as a new therapeutic agent in type 2 diabetes, affects circulating islet amyloid polypeptide (IAPP), a B-cell peptide of potential importance for diabetes pathophysiology.


METHODS
GLP-1 was administered in a buccal tablet (400 micrograms) to seven healthy subjects and nine subjects with type 2 diabetes. Serum IAPP and insulin levels were measured before and after GLP-1 administration.


RESULTS
In the fasting state, serum IAPP was 4.1 +/- 0.3 pmol/l in the controls vs 9.8 +/- 0.9 pmol/l in the subjects with type 2 diabetes (P < 0.001). IAPP correlated with insulin only in controls (r = 0.74, P = 0.002) but not in type 2 diabetes (r = 0.26, NS). At 15 min after GLP-1, circulating IAPP increased to (6.0 +/- 0.5 pmol/l in controls P = 0.009) and to 13.8 +/- 1.2 pmol/l in type 2 diabetes (P = 0.021). In both groups, serum insulin increased and blood glucose decreased compared with placebo. In controls serum IAPP increased in parallel with insulin (r = 0.79, P = 0.032), whereas in type 2 diabetes the increase in IAPP did not correlate with the increase in insulin.


CONCLUSIONS
Type 2 diabetes is associated with elevated circulating IAPP; GLP-1stimulates IAPP secretion both in healthy human subjects and in type 2 diabetes; IAPP secretion correlates with insulin secretion only in healthy subjects and not in type 2 diabetes.
Ahrén
B
B
Department of Medicine, Lund University, Malmö, Sweden.
Gutniak
M
M
D000328:Adult; D000682:Amyloid / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005215:Fasting; D005260:Female; D005934:Glucagon / Q000494:pharmacology*; D052216:Glucagon-Like Peptide 1; D006801:Humans; D007328:Insulin / Q000097:blood; D058228:Islet Amyloid Polypeptide; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000494:pharmacology*; D011498:Protein Precursors / Q000494:pharmacology*
D000682:Amyloid; D007328:Insulin; D058228:Islet Amyloid Polypeptide; D010446:Peptide Fragments; D011498:Protein Precursors; D052216:Glucagon-Like Peptide 1; D005934:Glucagon