Elzanaty S, Giwercman Y L, Giwercman A
Scanian Andrology Centre, Fertility Centre, Malmö University Hospital, Lund University, Malmö, Sweden.
Int J Androl. 2006 Jun;29(3):414-20. doi: 10.1111/j.1365-2605.2005.00625.x. Epub 2006 Feb 20.
Androgens, including 5alpha-dihydrotestosterone (DHT), are known to play a role for spermatogenesis and accessory sex gland function. The enzyme 5alpha-reductase (SRD5A) catalyses the conversion of testosterone to DHT. Our objective was to investigate whether polymorphisms in the SRD5A2 gene influence semen parameters in the general population. DNA from 182 Swedish military conscripts was examined for the A49T, V89L, and R227Q polymorphisms in the SRD5A type 2 gene. Ejaculates were analysed according to WHO guidelines. In addition, sperm motility was assessed using computer-aided sperm analysis (CASA). Seminal markers of epididymal (neutral alpha-glucosidase), prostatic (prostate specific-antigen and zinc), and seminal vesicles function (fructose) were measured. The A49TT-allele was associated with significantly higher sperm concentration compared with the wild type A-allele (mean: 102 x 10(6)/mL vs. 57 x 10(6)/mL, p = 0.02). The V89LV-genotype was correlated with significantly higher proportion progressive motile spermatozoa compared with the L-variant (mean: 55% vs. 48%, p = 0.04). The same trend was found regarding the CASA motile spermatozoa (mean: 52% vs. 41%, p = 0.02). No association between any of the polymorphisms and biochemical markers was found. SRD5A2 gene variants were associated with sperm concentration and motility, but not with epididymal and accessory sex gland markers. This effect on sperm parameters might therefore be exerted via a direct effect of DHT on spermatogenesis.
雄激素，包括5α - 双氢睾酮（DHT），已知对精子发生和附属性腺功能起作用。5α - 还原酶（SRD5A）催化睾酮转化为DHT。我们的目的是研究SRD5A2基因多态性是否影响普通人群的精液参数。检测了182名瑞典应征入伍者的DNA中SRD5A2型基因的A49T、V89L和R227Q多态性。根据世界卫生组织指南对精液进行分析。此外，使用计算机辅助精子分析（CASA）评估精子活力。测量附睾（中性α - 葡萄糖苷酶）、前列腺（前列腺特异性抗原和锌）和精囊功能（果糖）的精液标志物。与野生型A等位基因相比，A49TT等位基因与显著更高的精子浓度相关（平均值：102×10⁶/mL对57×10⁶/mL，p = 0.02）。与L变异体相比，V89LV基因型与显著更高比例的进行性活动精子相关（平均值：55%对48%，p = 0.04）。关于CASA活动精子也发现了相同趋势（平均值：52%对41%，p = 0.02）。未发现任何多态性与生化标志物之间存在关联。SRD5A2基因变异与精子浓度和活力相关，但与附睾和附属性腺标志物无关。因此，这种对精子参数的影响可能是通过DHT对精子发生的直接作用来实现的。
