Glucokinase gene islet promoter region variant (G-->A) at nucleotide -30 is not associated with reduced insulin secretion in Finns.
OBJECTIVE
To investigate the effect of the islet promoter region variant (G-->A) at nucleotide -30 of the glucokinase (GCK) gene on insulin levels in subjects with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and NIDDM.


METHODS
The study population included 294 subjects with NGT, 83 subjects with IGT, and 36 subjects with NIDDM. Oral glucose tolerance tests (OGTTs) were performed in all subjects, and intravenous glucose tolerance tests (IVGTTs) were performed in subjects with NGT. The islet promoter region of the GCK gene was amplified with polymerase chain reaction and screened for the variant (-30) using single-strand conformation polymorphism analysis.


RESULTS
The islet promoter variant (-30) of the GCK gene was found in 17% of subjects with NGT, 23% of subjects with IGT, and 14% of patients with NIDDM (NS between the groups). Fasting, 1-h, and 2-h insulin levels, measured by OGTT, did not differ between subjects with and without this variant in any of the three groups. Furthermore, first-phase insulin secretion, determined by an IVGTT in subjects with NGT, did not associate with presence of the islet promoter region variant (-30) of the GCK gene.


CONCLUSIONS
These results indicate that the variant (-30) of the islet promoter region of the GCK gene does not have a significant effect on insulin secretion in Finnish subjects with NGT, IGT, or NIDDM.
Rissanen
J
J
Department of Medicine, University of Kuopio, Finland.
Saarinen
L
L
Heikkinen
S
S
Kekäläinen
P
P
Mykkänen
L
L
Kuusisto
J
J
Deeb
S S
SS
Laakso
M
M
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000483:Alleles; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics; D005215:Fasting; D005260:Female; D005387:Finland / Q000453:epidemiology; D005796:Genes / Q000235:genetics*; D014644:Genetic Variation; D005941:Glucokinase / Q000235:genetics*; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism; D018149:Glucose Intolerance / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics; D005951:Glucose Tolerance Test; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007275:Injections, Intravenous; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D017354:Point Mutation / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics
D007328:Insulin; D005941:Glucokinase; D005947:Glucose