Changes in amylin and amylin-like peptide concentrations and beta-cell function in response to sulfonylurea or insulin therapy in NIDDM.
OBJECTIVE
Amylin, a secretory peptide of beta-cells, is the constituent peptide of islet amyloid, which is characteristic of NIDDM, and changes in amylin secretion in response to therapies may influence the rate of production of islet amyloid. The primary objective of this study was to determine whether therapy with sulfonylurea or basal insulin in NIDDM would alter amylin secretion in a way that might affect the formation of islet amyloid.


METHODS
In a randomized crossover design, eight subjects with NIDDM underwent three 8-week periods of therapy with diet alone, sulfonylurea, or exogenous basal insulin, with evaluation of amylin, amylin-like peptide (ALP), and glucose and C-peptide concentrations, both during fasting and after a standard breakfast. Changes in beta-cell function (% beta) were assessed, in the basal state by homeostasis model assessment (HOMA) and in the stimulated state by hyperglycemic clamps. Seven nondiabetic control subjects each underwent a meal profile and hyperglycemic clamp.


RESULTS
Both sulfonylurea and insulin therapy reduced basal glucose concentrations compared with diet alone, but neither reduced the increased postprandial glucose increments. Both sulfonylurea and insulin therapy increased basal % beta, assessed by HOMA, but only sulfonylurea increased the second-phase C-peptide responses to the hyperglycemic clamp. Sulfonylurea increased time-averaged mean postprandial amylin and ALP concentrations compared with diet alone (geometric mean [1-SD range] for amylin, 4.9 [2.0-11.8] vs. 3.0 [1.4-6.2] pmol/l, P = 0.003; for ALP, 16.4 [8.5-31.7] vs. 10.1 [4.9-20.8] pmol/l, P = 0.001). Insulin therapy reduced basal ALP concentrations compared with diet alone (2.9 [1.5-5.6] vs. 6.0 [2.6-13.6] pmol/l, P = 0.03), but had no effect on postprandial concentrations of amylin (3.0 [1.3-6.5] pmol/l) or ALP (10.0 [5.5-18.1] pmol/l).


CONCLUSIONS
By increasing postprandial concentrations of the constituent peptides of islet amyloid, sulfonylurea therapy might increase the rate of deposition of islet amyloid and thereby accelerate the decline of % beta in NIDDM, compared with diet therapy alone.
Rachman
J
J
Nuffield Department of Clinical Medicine, University of Oxford, U.K.
Payne
M J
MJ
Levy
J C
JC
Barrow
B A
BA
Holman
R R
RR
Turner
R C
RC
D000368:Aged; D000682:Amyloid / Q000097:blood / Q000187:drug effects*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D002096:C-Peptide / Q000097:blood / Q000187:drug effects; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D005215:Fasting; D005260:Female; D005947:Glucose / Q000378:metabolism; D015309:Glucose Clamp Technique; D006442:Glycated Hemoglobin / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D058228:Islet Amyloid Polypeptide; D007515:Islets of Langerhans / Q000187:drug effects* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D013453:Sulfonylurea Compounds / Q000627:therapeutic use*
D000682:Amyloid; D001786:Blood Glucose; D002096:C-Peptide; D005947:Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; D058228:Islet Amyloid Polypeptide; D013453:Sulfonylurea Compounds