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Other Original Articles: Marcello Maggio, Shehzad Basaria, Alessandro Ble, Fulvio Lauretani, Stefania Bandinelli, Gian Paolo Ceda, Giorgio Valenti, Shari M. Ling, and Luigi Ferrucci Correlation between Testosterone and the Inflammatory Marker Soluble Interleukin-6 Receptor in Older Men J Clin Endocrinol Metab 2006; 91: 345-347 [Abstract] [Full text] [PDF]

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Testosterone and interleukin-6 in young men at increased risk of type 2 diabetes.

Karsten Müssig, Silke A. Schäfer, Hans-Ulrich Häring, and Andreas Fritsche   (31 January 2006)

Testosterone and interleukin-6 in young men at increased risk of type 2 diabetes. 31 January 2006
Karsten Müssig, MD Department of Endocrinology, Metabolism and Pathobiochemistry, University Hospital of Tübingen, Silke A. Schäfer, Hans-Ulrich Häring, and Andreas Fritsche Send letter to journal: Re: Testosterone and interleukin-6 in young men at increased risk of type 2 diabetes. karsten.muessig{at}med.uni-tuebingen.de Karsten Müssig, et al.	We have read with interest the article of Maggio et al. (1) reporting on a positive correlation between testosterone and the soluble interleukin-6 receptor, but not tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, and C-reactive protein (CRP) in older men. Recently, we investigated the association between testosterone and inflammatory cytokines in young men at increased risk of type 2 diabetes (overweight or positive family history of type 2 diabetes). The study population consisted of 98 nondiabetic men with a mean age of 32 years (95% CI: 19-53) and a mean body mass index (BMI) of 25.4 kg/m² (95% CI: 19 -44). Mean concentration of total testosterone was 583 ng/dl (95% CI: 219-998). Mean concentrations of inflammatory markers were: 0.3 mg/dl (95% CI: 0.1-1.9) for CRP, 1.0 pg/ml (95% CI: 0.2-2.7) for IL-6, and 4.7 pg/ml (95% CI: 0.4-42) for TNF-α, respectively. In accordance with the results of Maggio et al. in older men, we did not find a correlation between testosterone and IL-6 concentrations in our population of young men (r=0.45, p=0.09). Furthermore, concentrations of CRP (r=0.40, p=0.06) and TNF-α (r=0.31, p=0.21) were also not correlated with testosterone levels. Testosterone and insulin sensitivity estimated from the OGTT were strongly correlated in our study population (r=0.62, p<0.0001) confirming previous reports (2). Therefore, our data do not support testosterone as a mediator of IL-6 actions on insulin sensitivity. We suggest that other mechanisms of IL-6, such as direct cellular actions (3, 4), play a major role in the development of insulin resistance. References 1. Maggio M, Basaria S, Ble A, Lauretani F, Bandinelli S, Ceda GP, Valenti G, Ling SM, Ferrucci L 2006 Correlation between Testosterone and the Inflammatory Marker Soluble Interleukin-6 Receptor in Older Men. J Clin Endocrinol Metab 91:345-347 2. Kapoor D, Malkin CJ, Channer KS, Jones TH 2005 Androgens, insulin resistance and vascular disease in men. Clin Endocrinol (Oxf) 63:239-250 3. Rotter V, Nagaev I, Smith U 2003 Interleukin-6 (IL-6) induces insulin resistance in 3T3-L1 adipocytes and is, like IL-8 and tumor necrosis factor-alpha, overexpressed in human fat cells from insulin- resistant subjects. J Biol Chem 278:45777-45784 4. Weigert C, Hennige AM, Lehmann R, Brodbeck K, Baumgärtner F, Schäuble M, Häring HU, Schleicher ED 2006 Direct cross-talk of interleukin-6 and insulin signal transduction via insulin receptor substrate-1 in skeletal muscle cells. J Biol Chem [Jan 2006; doi:10.1074/jbc.M509782200]