help button home button Endocrine Society JCEM JCEM Call for Nominations for EIC
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Submit a related Letter to the Editor
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Urhammer, S. A.
Right arrow Articles by Pedersen, O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Urhammer, S. A.
Right arrow Articles by Pedersen, O.
The Journal of Clinical Endocrinology & Metabolism Vol. 85, No. 9 3151-3154
Copyright © 2000 by The Endocrine Society

Original Studies

Studies of the Synergistic Effect of the Trp/Arg64 Polymorphism of the ß3-Adrenergic Receptor Gene and the -3826 A->G Variant of the Uncoupling Protein-1 Gene on Features of Obesity and Insulin Resistance in a Population-Based Sample of 379 Young Danish Subjects1

Søren A. Urhammer, Torben Hansen, Knut Borch-Johnsen and Oluf Pedersen

Steno Diabetes Center and Hagedorn Research Institute (S.A.U., T.H., K.B.-J., O.P.); and Center of Preventive Medicine, Glostrup University Hospital (K.B.-J.), DK-2820 Gentofte, Copenhagen, Denmark

Address all correspondence and requests for reprints to: Søren A. Urhammer, M.D., Steno Diabetes Center, Niels Steensens Vej 2, DK-2820 Gentofte, Copenhagen, Denmark.


   Abstract
Top
 Abstract
Introduction
 Subjects and Methods
 Results and Discussion
 Call for Papers for...
 References
 
This study examined whether the simultaneous presence of the previously identified Trp/Arg64 polymorphism of the ß3-adrenergic receptor (BAR) gene and the -3826 A->G nucleotide variant of the uncoupling protein-1 (UCP1) gene are associated with obesity, insulin resistance, or alterations in size at birth in a Danish study population comprising 379 unrelated young Caucasian subjects. All study participants underwent an iv glucose tolerance test with addition of tolbutamide after 20 min. In addition, a number of biochemical and anthropometric measures were performed on each subject. The subjects were genotyped for the 2 polymorphisms by applying PCR-restriction fragment length polymorphism. The subjects were divided into 4 groups according to their BAR and UCP1 genotype: wild-type carriers (n = 184), only Trp/Arg64 carriers (n = 29), only A->G UCP1 carriers (n = 146), and carriers of both genetic variants (n = 20). There were no differences across the genotype groups with respect to body mass index, fat mass, waist to hip ratio, birth weight or length, ponderal index, or weight gain during childhood or adolescence, nor was the combined genotype related to alterations in fasting serum levels of lipids, insulin, or C peptide or the insulin sensitivity index. In conclusion, the present study failed to demonstrate an additive or synergistic effect of the Trp/Arg64 variant of the BAR gene and the -3826 A->G variant of the UCP1 gene on the development of obesity and insulin resistance among randomly recruited Danish Caucasian subjects.


   Introduction
Top
 Abstract
 Introduction
Subjects and Methods
 Results and Discussion
 Call for Papers for...
 References
 
OBESITY IS, with rare exceptions, a complex phenotype resulting from interactions between environmental and genetic risk factors. The importance of genetic determinants has been evidenced by twin studies (1, 2) as well as studies of adopted children (3, 4, 5), showing that most familial aggregation of obesity is due to genetic influence rather than to shared family environment. Although numerous obvious candidate genes for obesity have been examined during recent years, the specific genetic defects responsible for the majority of human obesity have not been elucidated. This lack of results might reflect the heterogeneity of the disorder. Due to genetic interaction, it is likely that gene defects, showing no or only minor effect when expressed alone, might actually exhibit an influence on the phenotype when present in combination. The Trp/Arg64 polymorphism of the ß3-adrenergic receptor (BAR) gene, initially reported to be associated with accelerated weight gain, decreased energy expenditure, and reduced insulin sensitivity (6, 7, 8), has been extensively investigated during recent years. Several studies reported associations of the polymorphism with different estimates of obesity and insulin resistance, whereas just as many studies have failed to demonstrate any functional impact of this amino acid substitution. The inconsistency was recently emphasized when meta-analyses of the variant showed opposite results (9, 10). Controversy also exists concerning the impact of a A->G polymorphism at position -3826 in the promoter of the uncoupling protein-1 (UCP1) gene. This variant has been linked to increased capacity to gain weight in Canadians (11) and French subjects (12), whereas we recently failed to demonstrate any functional significance of the substitution on insulin resistance and obesity among young healthy Caucasians (13). Interestingly, an additive effect of the Trp/Arg64 polymorphism of the BAR gene and the A->G UCP1 promoter variant has recently been observed on weight gain among obese French subjects (12), resting metabolic rate in obese Finns (14), resistance to weight loss and maintenance of weight loss in obese Japanese subjects (15), and premenopausal obesity in Finnish women (16), supporting the hypothesis that obesity to some extent may result from interactive genetic factors. To address this issue in the Danish population we examined the effects of combined genotypes of the Trp/Arg64 variant of the BAR gene and the A->G variant of the UCP1 gene on estimates of obesity, insulin resistance, and size at birth in a population-based sample of young healthy Danes.


   Subjects and Methods
Top
 Abstract
 Introduction
 Subjects and Methods
Results and Discussion
 Call for Papers for...
 References
 
Subjects

The study population comprised 379 subjects randomly recruited from a population of young Caucasian individuals, aged 18–32 yr (17). The original data for birth length and birth weight of 331 of 380 subjects could be obtained from the midwife records stored in the Danish Provincial Archives for Zealand, Lolland/Falster, and Bornholm Islands. Ponderal index was calculated as (birth weight)/(birth length)3. Fat mass was measured using an impedance technique (18). Physiological and anthropometric characteristics of this population sample have been presented previously (17).

Before participation, informed consent was obtained from all subjects. The study was approved by the ethical committee of Copenhagen and was in accordance with the principles of the Declaration of Helsinki II.

Biochemical studies

The concentrations of fasting serum triglyceride, total cholesterol, and high density lipoprotein (HDL) cholesterol (Roche Molecular Biochemicals, Mannheim, Germany) were analyzed using standardized methods. Low density lipoprotein (LDL) cholesterol was calculated as serum total cholesterol - serum HDL cholesterol - serum triglyceride/2.2. Serum insulin was determined by enzyme-linked immunosorbent assay with a narrow specificity excluding des(31, 32) and intact proinsulin (19). Serum C peptide was determined by RIA (20), employing the polyclonal antibody M1230 (21, 22).

Measurements of insulin sensitivity index

The insulin sensitivity index was estimated from an iv glucose tolerance test in combination with injection of iv tolbutamide as previously described (17).

Detection of the Trp/Arg64 in the ß3-adrenergic receptor gene and the -3826 A->G polymorphism of the uncoupling protein-1 gene

Polymorphisms were detected using PCR-restriction fragment length polymorphism as previously described (13, 23).

Statistics

Differences in continuous variables between groups of subjects were tested with a generalized linear model, including genotype and gender as fixed variables and age as a covariate factor. Age was not included in the analyses of birth weight, birth length, or ponderal index. Body mass index (BMI) was also included as a covariate factor in the analyses of serum insulin and C peptide and the insulin sensitivity index. Data represent means (SD). P < 0.05 (two-tailed) was considered significant. The Statistical Package of Social Science (SPSS, Inc., Chicago, IL) for Windows, version 9.0 was used for statistical analysis.


   Results and Discussion
Top
 Abstract
 Introduction
 Subjects and Methods
 Results and Discussion
Call for Papers for...
 References
 
The distribution of the genotypes defined by the Thr/Arg64 variant of the BAR gene and the -3826 A->G polymorphism of the UCP1 gene is presented in Table 1Go. The allele frequencies of the BAR and UCP1 variants were 7% (95% confidence interval, 5–10%) and 25% (22–28%), respectively, as presented previously (13, 23). The genotypes of the variants were found to be in Hardy-Weinberg equilibrium. The study population was divided into four groups according to the genotype of the two variants (Table 2Go): wild type (n = 184), only the A->G UCP1 variant (heterozygous and homozygous carriers; n = 146), only the Thr/Arg64 variant of the BAR gene (all were heterozygous carriers; n = 29), and both variants (n = 20). Using a generalized linear model we failed to demonstrate any significant difference across the four groups of genotypes with respect to BMI, body fat content, serum lipids, size at birth, weight gain during childhood and adolescence, or estimates of insulin sensitivity (Table 2Go). As we observed a tendency toward a reduced insulin sensitivity in the group of combined carriers (Table 2Go), we performed a subgroup analysis comparing carriers of both variants to the rest of the study population. However, this analysis revealed no significant difference between the groups (P = 0.11). Three subjects did carry the Thr/Arg64 variant of the BAR gene in its homozygous form, and they have previously been reported to be insulin resistant and obese (23). All of these subjects also carried the A->G variant of the UCP1 gene on one allele and were hence included in the group of combined genotype. Three subjects were homozygous for the UCP1 gene variant and heterozygous for the Trp/Arg64 variant. They did not differ from the rest with respect to the examined variables (data not shown).


View this table:
[in this window]
[in a new window]
  		Table 1. Distribution of genotypes defined by the Trp/Arg64 variant of the ß3-adrenergic receptor (BAR) gene and the -3826 A->G nucleotide variant of the uncoupling protein 1 (UCP1) promoter gene among 379 healthy young Danes

 

View this table:
[in this window]
[in a new window]
  		Table 2. Clinical and biochemical data of 379 young healthy Caucasians when classified in accordance to their combined genotype of the Trp/Arg64 variant of the ß-adrenergic receptor (BAR) gene and the A->G nucleotide variant of the uncoupling protein 1 (UCP1) promoter gene

 
In contrast with the results of the present study, previous studies have suggested a synergistic effect of the simultaneous presence of the A->G variant of the UCP1 gene and the Trp/Arg64 polymorphism of the BAR gene on different estimates of obesity. Clément et al. reported an additive effect of the two variants on weight gain during adolescence in a study population of 238 morbidly obese French subjects (24). Among 170 obese Finns, an additive effect was demonstrated on resting metabolic rate (RMR), whereas no effect on BMI or body composition was observed in this study (25). The latter might have been expected, as low RMR is a risk factor for weight gain (26). In 113 obese Japanese subjects (15) and in 77 premenopausal obese Finnish women (16), additive effects of the variants on resistance to weight loss and maintenance of weight loss in response to low caloric diet were demonstrated, whereas no effect on RMR was found. All previous studies failed to detect any relationship between the combination of the 2 variants and other estimates of obesity, i.e. BMI, body fat, or waist/hip ratio. Our study is not directly comparable with these studies. The present study population is young, not obese, and randomly recruited, whereas previous studies have examined older and selected groups of individuals. It is possible that the 2 variants in study groups of obese and especially in morbidly obese subjects are expressed due to genetic interaction with other obesity susceptibility genes specific for these groups of individuals. Furthermore, the discrepancy between the present and previous studies might reflect differences in ethnic (genetic) background. The allelic frequencies of the Arg/Trp64 and A->G variants in the present study are in accordance with frequencies found among French (24), Finns (16, 25), and Germans (27), whereas the frequencies of both variants are 2-fold higher among Japanese subjects (15, 28).

We also evaluated the effect of the simultaneous presence of the Arg/Trp64 and A->G variants on fasting values of serum insulin and C peptide and the insulin sensitivity index. However, no evidence for associations between combined genotypes and these estimates of insulin resistance was detected. This is in line with a recent study in 214 Japanese men showing no additive effect of the variants on glucose tolerance and insulin resistance (28). Likewise, a study of 343 German Caucasians revealed no synergistic effect of the variants on fasting insulin or C peptide concentrations or diabetic manifestations (27).

The major problem in analyzing combination of genotypes is the need for large study populations. Hence, most previous studies are based on a small number of study participants carrying both variants. Therefore, risks of statistical type I (and type II) errors have to be considered. The power of the present study to detect a 25% increase in weight gain during childhood in carriers of both variants compared to the rest of the studied subjects is more than 90%. It is therefore unlikely that our study represents false negative results. In general, most study populations, including that reported here, have been applied for the examination of many gene variants. Therefore, when interpreting the analysis of a single gene variant or a combination of gene variants in a study population, correction for multiple testing has to be considered; i.e. the level of significance must be defined on a lower level to minimize the risk of statistical type II errors.

In conclusion, the present study demonstrates that the combination of the Trp/Arg64 variant of the BAR gene and the -3826 A->G nucleotide substitution of the UCP1 gene has no synergistic effect on obesity or insulin resistance in the group of randomly recruited young healthy Danes examined here.


   Call for Papers for the Special June 2001 Issue
Top
 Abstract
 Introduction
 Subjects and Methods
 Results and Discussion
 Call for Papers for...
References
 
At the request of Endocrine Society president Dr. Benita Katzenellenbogen, The Journal of Clinical Endocrinology & Metabolism and the other \E Endocrine Society journals will devote their June 2001 issues to topics in Reproductive Hormones and Human Health. This theme will also be emphasized at the 83rd Annual Meeting of The Endocrine Society in Denver, Colorado, June 20–23.

The editors of The Journal of Clinical Endocrinology & Metabolismare seeking submissions for this special issue. Manuscripts reporting investigations of male or female reproduction in a variety of organ systems, including the skeleton, gastrointestinal tract, cardiovascular, mammary, immune and neuroendocrine systems, as well as the gonads and reproductive tracts, are welcome.

The deadline for submissions is DECEMBER 15, 2000. Please indicate explicitly in your cover letter that you wish to have the manuscript considered for the June 2001 issue.


   Acknowledgments
 
We thank Sandra Urioste, Annemette Forman, Lene Aabo, Dorte Gøth-Johansen, Bente Mottlau, Susanne Kjellberg, Lis Ølholm, and Maja Lis Halkjær for dedicated and careful technical assistance; and Grete Lademann for secretarial support.


   Footnotes
 
1 This work was supported by grants from the Danish Research Academy, the Danish Medical Research Council, the University of Copenhagen, the Velux Foundation, the Danish Diabetes Association, and the European Economic Community (BMH4-CT98–3084). Back

Received February 1, 2000.

Revised May 19, 2000.

Accepted June 5, 2000.


   References
Top
 Abstract
 Introduction
 Subjects and Methods
 Results and Discussion
 Call for Papers for...
 References
 

  1. Herskind AM, McGue M, Sorensen TI, Harvald B. 1996 Sex and age specific assessment of genetic and environmental influences on body mass index in twins. Int J Obes Rel Metab Disord. 20:106–113.
  2. Stunkard AJ, Harris JR, Pedersen NL, McClearn GE. 1990 The body-mass index of twins who have been reared apart. N Engl J Med. 322:1483–1487.[Abstract]
  3. Stunkard AJ, Sorensen TI, Hanis C, et al. 1986 An adoption study of human obesity. N Engl J Med. 314:193–198.[Abstract]
  4. Sorensen TI, Price RA, Stunkard AJ, Schulsinger F. 1989 Genetics of obesity in adult adoptees and their biological siblings. Br Med J. 298:87–90.
  5. Vogler GP, Sorensen TI, Stunkard AJ, Srinivasan MR, Rao DC. 1995 Influences of genes and shared family environment on adult body mass index assessed in an adoption study by a comprehensive path model. Int J Obes Rel Metab Disord. 19:40–45.
  6. Walston J, Silver K, Bogardus C, et al. 1995 Time of onset of non-insulin-dependent diabetes mellitus and genetic variation in the ß3-adrenergic-receptor gene. N Engl J Med. 333:343–347.[Abstract/Free Full Text]
  7. Widen E, Lehto M, Kanninen T, Walston J, Shuldiner AR, Groop LC. 1995 Association of a polymorphism in the ß3-adrenergic-receptor gene with features of the insulin resistance syndrome in Finns. N Engl J Med. 333:348–351.[Abstract/Free Full Text]
  8. Clement K, Vaisse C, Manning BS, et al. 1995 Genetic variation in the ß3-adrenergic receptor and an increased capacity to gain weight in patients with morbid obesity. N Engl J Med. 333:352–354.[Abstract/Free Full Text]
  9. Allison DB, Heo M, Faith MS, Pietrobelli A. 1998 Metaanalysis of the association of the trp64arg polymorphism in the ß(3) adrenergic-receptor with body-mass index. Int J Obes. 22:559–566.
  10. Fujisawa T, Ikegami H, Kawaguchi Y, Ogihara T. 1998 Metaanalysis of the association of Trp64Arg polymorphism of ß3-adrenergic receptor gene with body mass index. J Clin Endocrinol Metab. 83:2441–2444.[Abstract/Free Full Text]
  11. Oppert JM, Vohl MC, Chagnon M, et al. 1994 DNA polymorphism in the uncoupling protein (UCP) gene and human body fat. Int J Obes Rel Metab Disord. 18:526–531.[Medline]
  12. Clement K, Ruiz J, Cassarddoulcier AM, et al. 1996 Additive effect of a-]g-(-3826) variant of the uncoupling protein gene and the trp64arg mutation of the beta-3-adrenergic receptor gene on weight-gain in morbid-obesity. Int J Obes. 20:1062–1066.
  13. Urhammer SA, Fridberg M, Sorensen TI, et al. 1997 Studies of genetic variability of the uncoupling protein 1 gene in Caucasian subjects with juvenile-onset obesity. J Clin Endocrinol Metab. 82:4069–4074.[Abstract/Free Full Text]
  14. Valve R, Heikkinen S, Rissanen A, Laakso M, Uusitupa M. 1998 Synergistic effect of polymorphisms in uncoupling protein-1 and ß(3)-adrenergic receptor genes on basal metabolic-rate in obese Finns. Diabetologia. 41:357–361.[CrossRef][Medline]
  15. Kogure A, Yoshida T, Sakane N, Umekawa T, Takakura Y, Kondo M. 1998 Synergic effect of polymorphisms in uncoupling protein 1 and ß(3)-adrenergic receptor genes on weight loss in obese Japanese. Diabetologia. 41:1399.[CrossRef][Medline]
  16. Fogelholm M, Valve R, Kukkonen-Harjula K, et al. 1998 Additive effects of the mutations in the ß3-adrenergic receptor and uncoupling protein-1 genes on weight loss and weight maintenance in Finnish women. J Clin Endocrinol Metab. 83:4246–4250.[Abstract/Free Full Text]
  17. Clausen JO, Borch-Johnsen K, Ibsen H, et al. 1996 Insulin sensitivity index, acute insulin response, and glucose effectiveness in a population-based sample of 380 young healthy Caucasians. Analysis of the impact of gender, body fat, physical fitness, and life-style factors. J Clin Invest. 98:1195–1209.[Medline]
  18. Heitmann BI. 1990 Prediction of body water and fat in adult Danes from measurements of electrical impedance. A validation study. Int J Obes. 14:789–802.[Medline]
  19. Andersen L, Dinesen B, Jorgensen PN, Poulsen F, Roder ME. 1993 Enzyme immunoassay for intact human insulin in serum or plasma. Clin Chem. 39:578–582.[Abstract/Free Full Text]
  20. Heding LG. 1977 Specific and direct radioimmunoassay for human proinsulin in serum. Diabetologia. 13:467–474.[CrossRef][Medline]
  21. Faber OK, Binder C, Markussen J, et al. 1978 Characterization of seven C-peptide antisera. Diabetes. 27(Suppl 1):170–177.
  22. Faber OK, Markussen J, Naithani VK, Binder C. 1976 Production of antisera to synthetic benzyloxycarbonyl-C-peptide of human proinsulin. Hoppe Seylers Z Physiol Chem. 357:751–757.[Medline]
  23. Urhammer SA, Clausen JO, Hansen T, Pedersen O. 1996 Insulin sensitivity and body weight changes in young white carriers of the codon 64 amino acid polymorphism of the ß3-adrenergic receptor gene. Diabetes. 45:1115–1120.[Abstract]
  24. Clement K, Ruiz J, Cassard-Doulcier AM, et al. 1996 Additive effect of A->G (-3826) variant of the uncoupling protein gene and the Trp64Arg mutation of the ß3-adrenergic receptor gene on weight gain in morbid obesity. Int J Obes Rel Metab Disord. 20:1062–1066.
  25. Valve R, Heikkinen S, Rissanen A, Laakso M, Uusitupa M. 1998 Synergistic effect of polymorphisms in uncoupling protein 1 and ß3-adrenergic receptor genes on basal metabolic rate in obese Finns. Diabetologia. 41:357–361.
  26. Ravussin E, Lillioja S, Knowler WC, et al. 1988 Reduced rate of energy expenditure as a risk factor for body-weight gain. N Engl J Med. 318:467–472.[Abstract]
  27. Schaffler A, Palitzsch KD, Watzlawek E, et al. 1999 Frequency and significance of the A->G (-3826) polymorphism in the promoter of the gene for uncoupling protein-1 with regard to metabolic parameters and adipocyte transcription factor binding in a large population-based Caucasian cohort. Eur J Clin Invest. 29:770–779.[CrossRef][Medline]
  28. Hayakawa T, Nagai Y, Taniguchi M, et al. 1999 Phenotypic characterization of the ß3-adrenergic receptor mutation and the uncoupling protein 1 polymorphism in Japanese men. Metab Clin Exp. 48:636–640.



This article has been cited by other articles:


Home page
 Eur Respir JHome page
J. Pierola, A. Barcelo, M. de la Pena, F. Barbe, J. B. Soriano, A. Sanchez Armengol, C. Martinez, and A. Agusti
{beta}3-Adrenergic receptor Trp64Arg polymorphism and increased body mass index in sleep apnoea
Eur. Respir. J., October 1, 2007; 30(4): 743 - 747.
[Abstract] [Full Text] [PDF]

Home page
 J. Clin. Endocrinol. Metab.Home page
X. Wang, Y. Cui, X. Tong, H. Ye, and S. Li
Effects of the Trp64Arg Polymorphism in the {beta}3-Adrenergic Receptor Gene on Insulin Sensitivity in Small for Gestational Age Neonates
J. Clin. Endocrinol. Metab., October 1, 2004; 89(10): 4981 - 4985.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Submit a related Letter to the Editor
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Urhammer, S. A.
Right arrow Articles by Pedersen, O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Urhammer, S. A.
Right arrow Articles by Pedersen, O.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals