The Effect of testosterone on Vo2 max in Type 2 Diabetic Patients

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 524-553-Male Reproductive Endocrinology
Bench to Bedside
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-539
Sangmo Hong*1, Chang-Bum Lee2, Dong-Sun Kim3, Yongsoo Park4, You Hern Ahn5 and Woong Hwan Choi6
1Hanyang University, Gyeonggi, South Korea, 2Hanyang Univ, Guri, South Korea, 3Hanyang Univ, Seoul, South Korea, 4Hanyang Univ.,, Seoul, South Korea, 5Hanyang University Hospital, 6Hanyang Univ Hospital, Seoul, South Korea
Aim: Type 2 diabetes is associated with low total testosterone in cross sectional studies. Testosterone levels  correlate not only with insulin sensitivity but also with genetic(OXPHOS gene expression) and functional markers of mitochondrial function(VO2max). A decrease of lean body mass and increase in fat mass are observed in hypogonadal  men compared with age- and BMI-matched controls. Several studies show the conflicting results about the relationship between testosterone and lean body mass. So, we are to investigate factors associated with low testosterone levels in type 2 diabetic(T2DM) patients , and the effect of testosterone level on body composition and Vo2 max(exercise capacity).

Method: 30 T2DM patients are included in this study. Those who are taking medication and disease Which are affecting exercise capacity were excluded from this study. All subjects have taken baseline checkup including history taking and physical examinations and blood sampling. All bood sampling including Total and free testosterone was done between 6 AM and 9 AM. Measured metabolic parameters were HgbA1C, 24 hr Urine Protein and C-peptide, fasing glucose and insulin for HOMA-IR calculation, lipid profile. Hypogonadism was defined when Total testosterone was lower than 320ng/dl or free testosterone was lower than 65 pg/ml. Whole body composition was measured by DEXA method(Hologic,QDR 4500A). Maximal O2 uptake(VO2 max) was obtained using an incremental work conducted with a bicycle ergometer combined by continuous analysis of expired gas and minute ventilation(Jaeger,Oxicon).

Results: Hypogonadal men had a significantly lower VO2max(ml/Kg/min) than eugonadal Men( 27.1 vs 30.9: P <0.05). Among other factors including BMI, smoking, alcohol consumption, duration of diabetes, amount of proteinuria,  Age had a significant negative relation with testosterone and free testosterone levels. Total fat mass, central fat mass, lean body mass was not signicantly associated with testosterone levels. Total and free testosterone levels did not have any positive effect on insulin resistance index and lipid profile. Rather than total testosterone levels, free testosterone level has a more powerful biologic effect on exercise capacity(VO2max).

Conclusion: Among several factors including duration, BMI and body composition, age Is a sole significant predictor of total and free testosterone levels. Both Total and Free testosterone is not significantly associated with body coposition (increased lean body mass and decreased fat mass) in type 2 DM. Rather than Total testosterone, Free testosterone has a more significant biological effect on Vo2 max. Because significant number of patients had a long disease duration and most patients had been taking medication and/or subcutaneous insulin,HOMA-IR was not significantly associated with VO2max and Testosterone levels.

Nothing to Disclose: SH, CBL, DSK, YP, YHA, WHC

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