Tissue effects of saw palmetto and finasteride: use of biopsy cores for in situ quantification of prostatic androgens.
Marks LS, Hess DL, Dorey FJ, Luz Macairan M, Cruz Santos PB, Tyler VE.
Urological Sciences Research Foundation, Culver City, California, USA.
OBJECTIVES: To determine the effects of a saw palmetto herbal blend (SPHB) compared with finasteride on prostatic tissue androgen levels and to evaluate 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 groups of men with symptomatic benign prostatic hyperplasia: 15 men receiving 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 placebo, 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 becoming reversed (1.05 versus 3.63 ng/g) with chronic finasteride therapy. The finasteride effect was statistically significant for both androgens (P <0.01), and little overlap of individual values between finasteride-treated and control patients was seen. In the randomized trial, tissue DHT levels were reduced 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 androgen values obtained with needle biopsy specimens were similar-both for absolute values and the percentage of change-to those previously reported using surgically excised volumes of prostatic tissue. The quantification of prostatic androgens by assay of needle biopsies is thus feasible and offers the possibility of serial studies in individual patients. The SPHB-induced suppression of prostatic DHT levels, modest but significant in a randomized trial, lends an element of support to the hypothesis that inhibition of the enzyme 5-alpha reductase is a mechanism of action of this substance.
J Urol 2000 May;163(5):1408-12 Related Articles, Links
Saw palmetto for the treatment of men with lower urinary tract symptoms.
Gerber GS.
Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA.
PURPOSE: A comprehensive review of the literature on the use of saw palmetto in men with lower urinary tract symptoms is provided. MATERIALS AND METHODS: A literature search of studies that have assessed the mechanism of action and clinical results of saw palmetto in men with benign prostatic hyperplasia was performed. RESULTS: A variety of potential mechanisms of action of saw palmetto have been demonstrated through in vitro studies, including 5-alpha reductase inhibition, adrenergic receptor antagonism and intraprostatic androgen receptor blockade. Clinical evidence of the relevance of these effects is largely unavailable. The use of saw palmetto in men with benign prostatic hyperplasia is safe with no recognized adverse effects. No effect on serum prostate specific antigen has been noted. Placebo controlled trials and meta-analyses have suggested that saw palmetto leads to subjective and objective improvement in men with lower urinary tract symptoms. However, most studies are significantly limited by methodological flaws, small patient numbers and brief treatment intervals. CONCLUSIONS: Evidence suggests that saw palmetto may have a significant effect on urinary flow rates and symptom scores compared to placebo in men with lower urinary tract symptoms. However, large scale, placebo controlled trials are needed to assess the efficacy of saw palmetto.
