Foppiani L, Piredda S, Cavani S, De Cassana P, Valenti S, Giusti M
Dipartimento di Scienze Endocrinologiche e Metaboliche, Cattedra di Endocrinologia Università di Genova, Italia.
Arch Ital Urol Androl. 1999 Feb;71(1):7-12.
The pathogenetic role of varicocele in male infertility is still controversial. Although epidemiological data have clearly shown a higher incidence of varicocele in the population of subfertile and infertile patients, the real effectiveness of the surgical repair of varicocele, expressed as increase in the pregnancy rate, is still debated. The presurgical gonadotropin releasing hormone (GnRH) test is the most reliable predictive index of successful surgical outcome in terms of fertility. Only patients with an increased gonadotropin response (in particular FSH) to GnRH will benefit from the surgery. The aim of the present study was to evaluate the gonadotropin response to GnRH 50 micrograms i.v. in a group of patients with low-medium grade varicocele. At the beginning of the test, a fine needle was inserted into the forearm and kept patent by a saline solution. Blood samples were collected at the following experimental times: 0, +15, +30, +60, +90, +120 min. The stimulus was administered i.v. as bolus at time 0. The gonadotropin response to the stimulus and baseline levels of testosterone, PRL, 17 beta oestradiol and SHBG were compared with those of a control group. Moreover, all the patients underwent semen analysis after 3-7 days' abstinence and to ultrasound-doppler of the testis. Finally, we preliminarily looked for the presence of microdeletions on the Yq chromosome by polymerase chain reaction. No difference in baseline hormonal levels was found between the patients with varicocele and the controls; the LH response to GnRH was also similar in the two groups. The patients with varicocele showed a significantly (p = 0.03) higher FSH response (13.6 +/- 5.9 mUI/ml) to GnRH than controls (3.8 +/- 0.5 mUI/ml). A significant positive correlation (r = 0.6, p = 0.05) was found between LH peaks after GnRH testing and varicocele grade. Nine of 11 patients with varicocele showed significant seminal abnormalities (i.e., oligoasthenospermia): all patients showed a normal karyotype and no microdeletions were detected on the Yq chromosome. The authors underline the importance of presurgical GnRH testing in patients with low grade varicocele, given the close correlation between gonadotropin-stimulated peaks and varicocele grade found in the study. The presence of significant seminal abnormalities, even in patients with low grade varicocele, suggests the use of molecular genetic techniques to detect possible microdeletions on the Yq chromosome, which may be responsible for the infertility.
精索静脉曲张在男性不育症中的致病作用仍存在争议。尽管流行病学数据已明确显示，精索静脉曲张在亚生育和不育患者群体中的发病率较高，但精索静脉曲张手术修复以提高妊娠率的实际效果仍存在争议。术前促性腺激素释放激素（GnRH）试验是生育方面手术成功结果最可靠的预测指标。只有对GnRH促性腺激素反应（特别是FSH）增加的患者才能从手术中获益。本研究的目的是评估一组中低度精索静脉曲张患者静脉注射50微克GnRH后促性腺激素的反应。在试验开始时，将一根细针插入前臂，并用盐水溶液保持通畅。在以下实验时间采集血样：0、+15、+30、+60、+90、+120分钟。在时间0时静脉推注给予刺激。将刺激后促性腺激素反应以及睾酮、PRL、17β雌二醇和SHBG的基线水平与对照组进行比较。此外，所有患者在禁欲3 - 7天后进行精液分析，并对睾丸进行超声多普勒检查。最后，我们通过聚合酶链反应初步检测Yq染色体上微缺失的存在。精索静脉曲张患者与对照组之间在基线激素水平上未发现差异；两组中LH对GnRH的反应也相似。精索静脉曲张患者对GnRH的FSH反应（13.6 +/- 5.9 mUI/ml）显著高于对照组（3.8 +/- 0.5 mUI/ml）（p = 0.03）。在GnRH检测后的LH峰值与精索静脉曲张分级之间发现显著正相关（r = 0.6，p = 0.05）。11例精索静脉曲张患者中有9例表现出明显的精液异常（即少弱精子症）：所有患者核型均正常，且在Yq染色体上未检测到微缺失。作者强调了术前GnRH检测在低度精索静脉曲张患者中的重要性，鉴于该研究中发现促性腺激素刺激峰值与精索静脉曲张分级之间密切相关。即使在低度精索静脉曲张患者中存在明显的精液异常，也提示使用分子遗传学技术检测Yq染色体上可能的微缺失，这可能是导致不育的原因。
