A glucocorticoid receptor gene marker is associated with abdominal obesity, leptin, and dysregulation of the hypothalamic-pituitary-adrenal axis.
OBJECTIVE
Abdominal obesity has a key role in the pathogenesis of prevalent and serious diseases and has been shown to be associated with an altered hypothalamic-pituitary-adrenal (HPA) axis function, which is regulated by endocrine feedback mediated via hippocampal glucocorticoid receptors (GR).


METHODS
We examined the HPA axis function by repeated salivary samples for the assessment of cortisol, as well as other endocrine, anthropometric, metabolic, and circulatory variables in middle-aged Swedish men (n = 284). With the restriction enzyme BclI, variants of the GR gene (GRL) locus were identified and two alleles with fragment lengths of 4.5 and 2.3 kilobases (kb) were detected.


RESULTS
The observed frequencies were 40.1% for the 2.3- and 2.3-kb, 46.2% for the 4.5- and 2.3-kb, and 13.7% for the 4.5- and 4.5-kb genotypes. The larger allele (4.5 and 4.5 kb) was associated with elevated body mass index (BMI; p < 0.001), waist-to-hip circumference ratio (p = 0.015), abdominal sagittal diameter (p = 0.002), leptin (p < 0.001), and systolic blood pressure (borderline, p = 0.058). The 4.5- and 4.5-kb allele was associated with leptin after adjustment for BMI. Moreover, salivary cortisol values, particularly after stimulation by a standardized lunch (p = 0.040 to 0.086), were elevated in the men with the larger allele.


CONCLUSIONS
These results indicate that there is an association between a deficient GR function, defined as a poor feedback regulation of the HPA axis activity, and a polymorphic restriction site at the GR gene locus. An abnormal control of HPA axis function due to genetic alterations may contribute to the pathogenesis of abdominal obesity.
Rosmond
R
R
Department of Heart and Lung Diseases, Göteborg University, Sweden. rosmonr@pbrc.edu
Chagnon
Y C
YC
Holm
G
G
Chagnon
M
M
Pérusse
L
L
Lindell
K
K
Carlsson
B
B
Bouchard
C
C
Björntorp
P
P
D000273:Adipose Tissue / Q000503:physiopathology; D000483:Alleles; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure; D001824:Body Constitution; D015992:Body Mass Index; D015331:Cohort Studies; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification; D003907:Dexamethasone / Q000494:pharmacology; D015977:Eukaryotic Initiation Factor-1 / Q000097:blood; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007328:Insulin / Q000032:analysis; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000453:epidemiology / Q000235:genetics*; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D012150:Polymorphism, Restriction Fragment Length; D011965:Receptors, Glucocorticoid / Q000737:chemistry / Q000235:genetics*; D012469:Salivary Glands / Q000378:metabolism; D013548:Sweden / Q000453:epidemiology; D013739:Testosterone / Q000097:blood
D001786:Blood Glucose; D015977:Eukaryotic Initiation Factor-1; D005938:Glucocorticoids; D007328:Insulin; D020738:Leptin; D011965:Receptors, Glucocorticoid; D013739:Testosterone; D003907:Dexamethasone; D004247:DNA; D006854:Hydrocortisone