Androgen receptor gene polymorphism and sex hormones in elderly men:the Tromsøstudy

The aim of this study was to examine whether CAG/GGN repeats are significant modulators of serum concentrations of total and free testosterone(T)as well as of luteinizing hormone(LH)in elderly men.Sixty-nine 60-to 80-year-old men with subnormal T levels(≤11.0 nmol L^(-1))and 104 men with normal T levels taking part in a nested case-control study were used for these analyses.Sex hormones were measured and free T was calculated.The CAG and GGN polymorphisms in the androgen receptor gene were determined by polymerase chain reaction and subsequent direct sequencing.There were no differences in the CAG and GGN repeat lengths between the groups.In cross-sectional analyses of the whole cohort,total and free T were positively associated with CAG length(all P<0.05)before,but not after,waist circumference or body mass index was added to the model.CAG repeat lengths were weakly,but not independently,associated with total and free T.These findings indicate that when clinically evaluating T and LH levels in elderly men,the CAG and GGN repeat lengths do not need to be taken into consideration.

Seasonal fluctuation in the secretion of the antioxidant melatonin is not associated with alterations in sperm DNA damage

A high sperm DNA fragmentation index （DFI） is associated with reduced fertility. DFI is influenced by the balance between reactive oxygen species and antioxidants. A circannual variation in melatonin, an antioxidant and free radical scavenger, could thus impact semen quality and fertility. The association between the major melatonin metabolite, urine 6-sulfatoxymelatonin （aMT6s）, and DFI was analyzed in 110 Oslo men （south of the Arctic Circle） and 86 Tromsoe men （north of the Arctic Circle）. Two semen analyses, summer and winter, and four urine samples （early/late summer; early/late winter）, were analyzed. The associations between aMT6s in urine and DFI were characterized in a cross-sectional and longitudinal manner using correlation analysis and linear regression. Regardless of season and location, no significant correlations between aMT6s and DFI were observed. The correlation coefficients for associations between changes over time （early winter-early summer） in aMT6s and DFI were for the total cohort： rho = -0.08 （P = 0.322）, for the Oslo cohort： rho = -0.07 （P = 0.485）, and for the Tromsoe cohort： rho = -0.14 （P = 0.273）, respectively. Similar results were seen when comparing late winter and late summer. There was no any statistically significant correlation between changes over time in aMT6s and DFI for men with DFI below and above the median value （10%）, respectively. The seasonal variation in melatonin excretion seems not to have any impact on DFh