Tissue effects of saw palmetto and finasteride: Use of biopsy cores for insitu quantification of prostatic androgens

Objectives. To determine the effects of a saw palmetto herbal blend (SPHB) compared with finasteride on prostatic tissue androgen levels and to evalua te needle biopsies as a source of tissue for such determinations. Methods. Prostate levels of testosterone and dihydrotestosterone (DHT) were measured on 5 to 10-mg biopsy specimens (18-gauge needle cores) in three g roups of men with symptomatic benign prostatic hyperplasia: 15 men receivin g chronic finasteride therapy versus 7 untreated controls; 4 men undergoing prostate adenomectomy to determine sampling variability (10 specimens each ); and 40 men participating in a 6-month randomized trial of SPHB versus pl acebo, before and after treatment. Results. Prostatic tissue DHT levels were found to be several times higher than the levels of testosterone (5.01 versus 1.51 ng/g), that ratio becomin g reversed (1.05 versus 3.63 ng/g) with chronic finasteride therapy. The fi nasteride effect was statistically significant for both androgens (P <0.01) , and little overlap of individual values between finasteride-treated and c ontrol patients was seen. In the randomized trial, tissue DHT levels were r educed by 32% from 6.49 to 4.40 ng/g in the SPHB group (P <0.005), with no significant change in the placebo group. Conclusions. For control versus finasteride-treated men, the tissue androge n values obtained with needle biopsy specimens were similar-both for absolu te values and the percentage of change-to those previously reported using s urgically excised volumes of prostatic tissue. The quantification of prosta tic androgens by assay of needle biopsies is thus feasible and offers the p ossibility of serial studies in individual patients. The SPHB-induced suppr ession of prostatic DHT levels, modest but significant in a randomized tria l, lends an element of support to the hypothesis that inhibition of the enz yme 5-alpha reductase is a mechanism of action of this substance. UROLOGY; 57: 999-1005, 2001. (C) 2001, Elsevier Science Inc.