['The aim of this study was to assess whether low serum testosterone levels in men with newly diagnosed prostate cancer have an association to the endocrine status, prostate-specific antigen (PSA) levels, Gleason score, and androgen receptor expression.', 'Besides a full clinical work-up, the following hormones were quantified in men with newly diagnosed prostate cancer by serum analysis: total testosterone, human luteinising hormone (hLH), human follicle stimulating hormone (hFSH), estradiol, and dehydroepiandrostendione (DHEA). In a subgroup of men, androgen receptor expression was determined immunohistochemically.', 'One hundred and fifty six patients (65.7 +/- 8.5 yrs) with a mean PSA of 29.8 ng/ml (median: 7.4 ng/ml) were analysed. Fifty-two patients (33%) had a partial androgen deficiency (serum testosterone < 3.0 ng/ml). These men had lower hLH (3.3 vs. 5.9 mIU/ml), hFSH (6.2 vs. 8.4 mIU/ml), and estradiol (18.8 vs. 29.1 pg/ml) serum levels. Mean Gleason score was higher (7.4 vs. 6.2) in men with a low serum testosterone, PSA-levels were lower (25.3 vs. 31.9 ng/ml). Mean testosterone levels decreased from 4.1 +/- 1.7 ng/ml in patients with Gleason scores < or = 5 to 2.8 +/- 2.7 ng/ml with Gleason scores > or = 8. Androgen receptor expression was higher in patients with low serum testosterone.'] Is high-grade prostate cancer associated with low serum testosterone levels?