Gann P H, Chatterton R, Vogelsong K, Grayhack J T, Lee C
Department of Preventive Medicine, Robert H. Lurie Cancer Center, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Prostate. 1997 Sep 1;32(4):234-40. doi: 10.1002/(sici)1097-0045(19970901)32:4<234::aid-pros2>3.0.co;2-j.
Prostatic fluid (PF) provides a unique medium for noninvasive evaluation of critical growth and differentiation signals in the prostatic microenvironment. The purpose of this study was to establish the feasibility of measuring two prostatic mitogens, epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) in PF, and specifically to quantify extraneous variability attributable to the assay itself, sample handling, or biological variation within an individual over time.
PF was collected by transrectal massage from consecutive patients attending a urology clinic. Pooled PF and individual samples from 25 men with stable benign prostatic hyperplasia (BPH) were analyzed for EGF and TGF-alpha by radioimmunoassay and for total protein.
Reproducibility was adequate at dilutions as low as 1:50 (2-microliter pooled sample) and 1:5 (20 microliters) for EGF and TGF-alpha, respectively. Results were not affected by freeze-thaw cycles, time in storage, or protease inhibition in fresh PF. EGF and TGF-alpha were detectable in 100% and 92% of individual men, with respective means of 152 and 0.2 ng/ml. Correlations between two samples obtained from the same man within 12 months were highly significant (EGF r = 0.89, TGF-alpha r = 0.71). Protein concentrations were consistent over time; expression of either peptide per weight of protein rather than per volume did not improve within-man correlation. Between-man variability far exceeded within-man variability for both peptides, and was estimated to account for 84% and 61% of the total variability in EGF and TGF-alpha, respectively. There was no correlation between EGF and TGF-alpha in the same samples.
We conclude that men with BPH secrete consistent and distinct levels of EGF-related peptides in PF, and that these levels can be detected with acceptable sensitivity and precision by radioimmunoassay (RIA). Measurement of TGF-alpha, which has not been reported previously, requires a relatively larger sample.
前列腺液（PF）为无创评估前列腺微环境中的关键生长和分化信号提供了独特的介质。本研究的目的是确定测量PF中两种前列腺有丝分裂原，即表皮生长因子（EGF）和转化生长因子-α（TGF-α）的可行性，特别是量化由检测本身、样本处理或个体随时间的生物学变异引起的额外变异性。
通过经直肠按摩从一家泌尿外科诊所的连续患者中收集PF。采用放射免疫分析法对25例稳定良性前列腺增生（BPH）男性的混合PF和个体样本进行EGF和TGF-α分析，并测定总蛋白。
对于EGF和TGF-α，分别在低至1:50（2微升混合样本）和1:5（20微升）的稀释度下，重现性良好。结果不受冻融循环、储存时间或新鲜PF中蛋白酶抑制的影响。在100%和92%的个体男性中可检测到EGF和TGF-α，其平均值分别为152和0.2 ng/ml。在12个月内从同一男性获得的两个样本之间的相关性非常显著（EGF r = 0.89，TGF-α r = 0.71）。蛋白质浓度随时间保持一致；以每重量而非每体积的蛋白质计算的任一肽的表达并未改善个体内的相关性。两种肽的个体间变异性远超过个体内变异性，估计分别占EGF和TGF-α总变异性的84%和61%。同一样本中EGF和TGF-α之间无相关性。
我们得出结论，BPH男性在PF中分泌一致且独特水平的EGF相关肽，并且这些水平可以通过放射免疫分析（RIA）以可接受的灵敏度和精密度进行检测。此前未报道过的TGF-α的测量需要相对较大的样本。
