Androgen deficiency, diabetes, and the metabolic syndrome in men.
OBJECTIVE
The burden of androgen deficiency in men with diabetes and the metabolic syndrome has become increasingly apparent in population-based studies. This article focuses on the mechanisms underlying the interdependent relationship between these conditions.


RESULTS
Various definitions of hypogonadism, the metabolic syndrome and diabetes have been proposed and are used in the literature. Cross-sectional studies have found that between 20 and 64% of men with diabetes have hypogonadism, with higher prevalence rates found in the elderly. Hypogonadism can be a risk factor for the development of diabetes and the metabolic syndrome through various mechanisms including changes in body composition; androgen receptor polymorphisms; glucose transport; and reduced antioxidant effect. Conversely, diabetes and the metabolic syndrome can be risk factors for hypogonadism through some similar but mostly distinct mechanisms, such as increased body weight; decreased sex hormone binding globulin levels; suppression of gonadotrophin release or Leydig cell testosterone production; cytokine-mediated inhibition of testicular steroid production; and increased aromatase activity contributing to relative estrogen excess.


CONCLUSIONS
The relationship between diabetes, the metabolic syndrome and androgen deficiency is complex. Testosterone supplementation, by either oral or intramuscular routes and through exogenous or endogenous delivery, has a promising role in this population although further clinical trials are needed.
Kalyani
Rita R
RR
Division of Endocrinology and Metabolism, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA.
Dobs
Adrian S
AS
D017677:Age Distribution; D000728:Androgens / Q000172:deficiency*; D048909:Diabetes Complications / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000209:etiology / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007006:Hypogonadism / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology / Q000209:etiology; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications / Q000209:etiology / Q000378:metabolism*; D015995:Prevalence; D012307:Risk Factors; D012737:Sex Factors; D013739:Testosterone / Q000627:therapeutic use
D000728:Androgens; D013739:Testosterone; D005947:Glucose