Premium
Sex hormone–binding globulin at the crossroad of body composition, somatotropic axis and insulin/glucose homeostasis in young healthy men
Author(s) -
Vanbillemont Griet,
Lapauw Bruno,
De Naeyer Hélène,
Roef Greet,
Kaufman JeanMarc,
Taes Youri E. C.
Publication year - 2012
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2011.04155.x
Subject(s) - medicine , endocrinology , somatotropic cell , glucose homeostasis , homeostasis , insulin , hormone , biology , sex hormone binding globulin , insulin resistance , pituitary gland , androgen
Summary Objectives Sex hormone–binding globulin (SHBG) modulates the bioavailability of sex steroids at tissue level. Genetic, hormonal and lifestyle‐related factors determine the SHBG levels, and low SHBG levels are a known risk factor for the development of the metabolic syndrome, diabetes and cardiovascular diseases. We investigated to what extent different determinants contribute to the variation in SHBG levels in healthy young men. Design and patients Healthy male siblings ( n = 677) aged 25–45 year were recruited in a cross‐sectional, population‐based study. Measurements Lean and fat mass were measured using dual‐energy X‐ray absorptiometry (DXA), and immunoassays were used to determine the serum hormonal levels. Additional information about smoking and physical activity was obtained using questionnaires. Carriers of two SHBG polymorphisms, the Asp327Asn polymorphism and the (TAAAA) n repeat polymorphism, were identified. Results Weight, BMI, whole body fat mass and truncal fat mass were negatively associated with SHBG levels. Body composition characteristics did not differ between SHBG genotype groups, indicating that body composition controls SHBG levels rather than the other way around. The associations may be mediated by adipokines because leptin and adiponectin were, respectively, inversely and positively associated with SHBG levels. Insulin and glucose were negatively associated with SHBG levels, as well as IGF‐1 and IGF‐BP3, while no associations were found with free thyroid hormone status. Conclusions In conclusion, we found that fat mass, insulin and IGF‐1 levels are important negative determinants of SHBG levels in young healthy men. The association with fat mass could be mediated by the effects of adiponectin and/or leptin on SHBG synthesis.