Abstract
To investigate a possible role of an enteroinsular axis involvement in the pathogenesis
of type 2 diabetes, plasma glucagon-like peptide 1 (GLP-1) 7-36 amide response to
nutrient ingestion was evaluated in type 2 diabetics affected by different degrees
of β-cell dysfunction.
Methods: 14 patients on oral hypoglycaemic treatment (group A: HbA1C = 8.1 ± 1.8 %) and 11
age-matched diabetic patients on diet only (group B: HbA1C = 6.4 ± 0.9) participated
in the study. 10 healthy volunteers were studied as controls. In the postabsorptive
state, a mixed meal (700 kCal) was administered to all subjects, and blood samples
were regularly collected up to 180′ for plasma glucose, insulin, glucagon, and GLP-1
determination.
Results: In the control group, the test meal induced a significant increase in plasma GLP-1
at 30′ and 60′ (p < 0.01); the peptide concentrations then returning toward basal
levels. β-cell function estimation by HOMA score confirmed a more advanced involvement
in group A than in group B (p < 0.01). In contrast, the insulin resistance degree
showed a similar result in the two groups (HOMA-R). In group A, first-phase postprandial
insulin secretion (0 - 60’) resulted, as expected, in being significantly reduced
compared to healthy subjects (p < 0.001). In the same patients the mean fasting GLP-1
value was similar to controls, but the meal failed to increase plasma peptide levels,
which even tended to decrease during the test (p < 0.01). In group B, food-mediated
early insulin secretion was higher than in group A (p < 0.001), although significantly
reduced when compared to controls (p < 0.01). Like group A, no GLP-1 response to food
ingestion occurred in group B patients in spite of maintained basal peptide secretion.
Whereas the test-meal did not significantly modify plasma glucagon levels in the control
group, glucagon concentrations increased at 30’ and 60’ in both diabetic groups (p
< 0.01).
Conclusions: 1) The functional integrity of GLP-1 cells results as being seriously impaired even
in the condition of mild diabetes; 2) the early peptide failure could contribute to
the development of β-cell deterioration which characterizes overt type 2 diabetes.
Key words
GLP-1 - Enteroinsular Axis - Diabetes
References
1
United Kingdom Prospective Diabetes Study Group (UKPDS 34) .
Effect of intensive blood glucose control with metformin on complications in overweight
patients with type 2 diabetes.
Lancet.
1998;
352
854-865
2
Jones L C, Clark A.
B-cell neogenesis in type 2 diabetes.
Diabetes.
2001;
50 (Suppl. 1)
S186-S187
3
Weyer C, Bogardus C, Mott D M, Pratley R E.
The natural history of insulin secretory dysfunction and insulin resistance in the
pathogenesis of type 2 diabetes mellitus.
J Clin Invest.
1999;
104
787-794
4
Pimenta W, Korytkowski M, Mitrakou A, Jenssen T, Yki-Jarvinen H, Evron W, Dailey G,
Gerich J.
Pancreatic β-cell dysfunction as the primary genetic lesion in NIDDM. Evidence from
studies in normal glucose-tolerant individuals with a first-degree NIDDM relative.
JAMA.
1995;
273 (23)
1855-1861
5
United Kingdom Prospective Diabetes Study Group (UKPDS 13) .
Relative efficacy of randomly allocated diet, sulphonylurea, insulin, or metformin
in patients with newly diagnosed non insulin-dependent diabetes followed for three
years.
BMJ.
1995;
310
83
6
Rudenski A S, Hadden D R, Atkinson A B, Kennedy L, Matthews D R, Merrett J D, Pockaj B,
Turner R C.
Natural history of pancreatic islet b-cell function in type 2 diabetes mellitus studied
over six years by homeostasis model assessment.
Diab Med.
1988;
5
36-41
7
Sempoux C, Guiot Y, Dubois D, Moulin P, Rahier J.
Human type 2 diabetes. Morphological evidence for abnormal B-cell function.
Diabetes.
2001;
50 (Suppl. 1)
S172-S177
8
Kreymann B, Williams G, Ghatei M A, Bloom S R.
Glucagon-like peptide 1 (7-36): a physiological incretin in man.
Lancet.
1987;
ii
1300-1304
9
Drucker D J.
Glucagon-like peptides.
Diabetes.
1998;
47
59-169
10
Fehmann H C, Habener J F.
Insulinotropic glucagon-like peptide 1 (7-37)/(7-36 amide). A new incretin hormone.
Trends Endocrinol Metab.
1992;
3
158-163
11
Edwards C MB, Todd J F, Mahmoudi M, Wang Z, Wang R M, Ghatei M A, Bloom S R.
Glucagon-like peptide 1 has a physiological role in the control of postprandial glucose
in humans. Studies with the antagonist exendin 9-39.
Diabetes.
1999;
48
86-93
12
Nauck M, Stockmann F, Ebert R, Creutzfeldt W.
Reduced incretin effect in type 2 (non insulin-dependent) diabetes.
Diabetologia.
1986;
29
46-52
13
Tronier B, Dejgard A, Andersen T, Madsbad S.
Absence of incretin effect in obese type 2 and diminished effect in lean type 2 and
obese subjects.
Diabetes Res Clin Pract.
1985;
(Suppl. 1)
S568
14
Lugari R, Dell'Anna C, Ugolotti D, Dei Cas A, Marani B, Iotti M, Orlandini A, Zandomeneghi R,
Gnudi A.
Effect of nutrients ingestion on glucagon-like peptide 1 (GLP-1) 7-36 amide secretion
in human type 1 and type 2 diabetes.
Horm Met Res.
2000;
32
424-428
15
Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus.
Diabetes Care.
1998;
21 (1)
S5-S19
16
Haffner S M, Miettinen H, Stern M P.
The homeostasis model in the San Antonio heart study.
Diabetes Care.
1997;
20 (7)
1087-1092
17
Hermans M P, Levy J C, Morris R J, Turner R C.
Comparison of insulin sensitivity tests across a range of glucose tolerance from normal
to diabetes.
Diabetologia.
1999;
42
678-687
18
Bonora E, Targher G, Alberiche M, Bonadonna R C, Saggiani F, Zenere M B, Monauni T,
Muggeo M.
Homeostasis model assessment closely mirrors the glucose clamp technique in the assessment
of insulin sensitivity.
Diabetes Care.
2000;
23
57-63
19
United Kingdom Prospective Diabetes Study Group (UKPDS 33).
Intensive blood-glucose control with sulphonylureas or insulin compared with conventional
treatment and risk of complications in patients with type 2 diabetes.
Lancet.
1998;
352
837-853
20
Luzi L, DeFronzo R A.
Effect of loss of first-phase insulin secretion on hepatic glucose production and
tissue glucose disposal in humans.
Am J Physiol.
1989;
257
E241-E246
21
Miyawaki K, Yamada Y, Yano H, Niwa H, Ban N, Ihara Y, Kubota A, Fujimoto S, Kajikawa M,
Kuroe A, Tsuda K, Hashimoto H, Yamashita T, Jomori T, Tashiro F, Miyazaki J, Seino Y.
Glucose intolerance caused by a defect in the enteroinsular axis: A study in gastric
inhibitory polypeptide receptor knockout mice.
PNAS.
1999;
96 (26)
14 843-14 847
22
Scrocchi L A, Brown T J, Ma Klusky N, Brubaker P L, Auerbach A B, Joyner A L, Drucker D J.
Glucose intolerance but normal satiety in mice with a null mutation in the glucagon-like
peptide 1 receptor gene.
Nat Med.
1996;
2 (11)
1254-1258
23
Ahren B, Larsson H, Holst J J.
Reduced gastric inhibitory polypeptide but normal glucagon-like peptide 1 response
to oral glucose in postmenopausal women with impaired glucose tolerance.
Eur J Endocrinol.
1997;
137
127-131
24
Byrne M M, Gliem K, Wank U, Arnold R, Katschinski M, Polonsky K S, Goke B.
Glucagon-like peptide 1 improves the ability of the β-cell to sense and respond to
glucose in subjects with impaired glucose tolerance.
Diabetes.
1998;
47
1259-1265
25
Broderick C L, Heisserman J A, Miller A R.
Effect of sub-chronic administration of GLP1 (7-37) on β-cell failure in Zucker diabetic
rats.
Diabetologia.
1995;
38 (1)
A171
26
Holz G G, Kuhtreiber W M, Habener J F.
Pancreatic β-cells are rendered glucose-competent by the insulinotropic hormone glucagon-like
peptide 1 (7-37).
Nature.
1993;
361
362-365
27
Gutniak M, Orskov C, Holst J J, Ahren B, Efendic S.
Antidiabetogenic effect of glucagon-like peptide 1 (7-36 amide) in normal subjects
and in patients with diabetes mellitus.
N Engl J Med.
1992;
326
1316-1322
28
Nauck M A.
Glucagon-like peptide 1: a potent gut hormone with a possible therapeutic perspective.
Acta Diabetol.
1998;
35
117-129
29
Rachman J, Barrow B A, Levy J C, Turner R C.
Near-normalisation of diurnal glucose concentrations by continuous administration
of glucagon-like peptide 1 (GLP-1) in subjects with NIDDM.
Diabetologia.
1997;
40
205-211
30
Nauck M A, Heimesaat M M, Orskov C, Holst J J, Ebert R, Creutzfeldt W :.
Preserved incretin activity of glucagon-like peptide 1 (7-36 amide) but not of synthetic
human gastric inhibitory polypeptide in patients with type 2 diabetes mellitus.
J Clin Invest.
1993;
91
301-307
31
Lefebvre P J, Scheen A J.
The postprandial state and risk of cardiovascular disease.
Diabet Med.
1998;
15 (4)
S63-S68
32
Ceriello A.
The post-prandial state and cardiovascular disease: relevance to diabetes mellitus.
Diabetes Res Rev.
2000;
16 (2)
125-132
Dr. Roberta Lugari
Cattedra di Endocrinologia
Via Gramsci 14 · 43100 Parma · Italy
Phone: + 39 (521) 290 778 ·
Fax: + 39 (521) 982 943
Email: endoparm@ipruniv.cce.unipr.it