Pleiotropic relationships between cortisol levels and adiposity: The HERITAGE Family Study.
OBJECTIVE
To investigate familial basis for the relationship between cortisol adiposity at baseline and their training responses.


METHODS
Bivariate correlation and segregation analyses were employed between cortisol and several adiposity measures [body mass index, fat mass (FM), fat-free mass, percentage of body fat (% BF), abdominal visceral fat (AVF), abdominal subcutaneous fat (ASF), and abdominal total fat (ATF)] from 99 white families and 105 black families.


RESULTS
In both races, significant inverse phenotypic correlations were generally observed between cortisol and adiposity measures at baseline but not for training responses. Significant cross-trait familial correlations were found for cortisol with abdominal fat (ASF, AVF, ATF) and overall body adiposity (FM, % BF) measures at baseline, which accounted for 14% to 20% of the phenotypic variance in whites. The cross-trait correlations were not significant for baseline phenotypes in blacks, perhaps because of the small sample size. A bivariate segregation analysis showed evidence of polygenic pleiotropy for cortisol with both abdominal fat and overall adiposity measures that accounted for 14% to 17% of the phenotypic covariance, but major gene pleiotropy was not suggested in whites. However, when ASF, AVF, and ATF were additionally adjusted for FM, no familial cross-trait correlations or polygenic pleiotropy between cortisol and the abdominal fat measures remained.


CONCLUSIONS
Evidence was found for polygenic pleiotropy but not for pleiotropic major gene effects between cortisol and overall adiposity in whites. However, the covariation of cortisol with abdominal fat phenotypes is dependent on concomitant polygenic factors for total-body fat.
Feitosa
Mary F
MF
Division of Biostatistics, Washington University School of Medicine, Saint Louis, Missouri 63110, USA. maryf@wubios.wustl.edu
Rice
Treva
T
Rosmond
Roland
R
Rankinen
Tuomo
T
Leon
Arthur S
AS
Skinner
James S
JS
Wilmore
Jack H
JH
Bouchard
Claude
C
Rao
D C
DC
D000005:Abdomen; D000273:Adipose Tissue; D044383:Black People; D001823:Body Composition / Q000235:genetics*; D015992:Body Mass Index; D006801:Humans; D006854:Hydrocortisone / Q000097:blood* / Q000235:genetics; D020412:Multifactorial Inheritance; D010641:Phenotype; D010807:Physical Endurance; D014781:Viscera; D044465:White People
D006854:Hydrocortisone