Quantification of Prostatic Androgens
Part 2. Effect of Saw Palmetto Herbal Blend

Leonard S Marks, Culver City, CA, David L Hess, Beaverton, OR, Frederick J Dorey, Los Angeles, CA, Alan W Partin, Jonathan I. Epstein, Baltimore, MD, Maria L Macairan, Los Angeles, CA, Varro E Tyler, West Lafayette, IN. (Presentation by Dr. Marks)

Abstract to be presented at the 2001 AUA Meeting in Anaheim, CA on Wednesday, June 5, 2001.

INTRODUCTION AND OBJECTIVES: Saw palmetto (SP) is widely used for symptomatic BPH, but its mechanisms are unknown. To evaluate the possibility that SP inhibits 5 alpha-reductase (5AR), we developed an in situ method for determination of prostatic tissue levels of testosterone (T) and dihydrotestosterone (DHT) and applied it to men in a randomized trial, Saw Palmetto Herbal Blend (SPHB) v PBO.

MATERIALS AND METHODS: Men with BPH had sextant biopsy of prostate (P) (18 ga. needle cores) at baseline and after 6 months of treatment with PBO (n = 20) or a standardized SPHB (320 mg/d of SP) (n = 20). PBO and SPHB patients were matched at baseline for age (64 yrs), symptoms (IPSS = 17), uroflow (Qmax = 10.5 cc/sec), P volume (56 cc), and PSA (3.3 ng/ml). For each man, 2 midsagittal P cores were quick frozen upon extraction and batch-analyzed at end of study for T, DHT, and Estradiol (E) (method in companion abstract). Other P cores were used for routine histology and to quantify tissue components morphometrically.

RESULTS: P levels of T (1.4-1.6 ng/g) and DHT (5.4-6.5 ng/g) were similar in the two groups at baseline (p = NS). After treatment, T did not change in either group, but in the SPHB group, median DHT decreased to 4.4 ng/g (p = 0.005, sign rank test), a 32% change from baseline. No significant change in median DHT levels was seen in the PBO group (p = NS). E was not detectable before or after treatment. No change in serum levels of T, DHT, or E was observed. No correlation was seen between tissue DHT changes and clinical changes or the SPHB-induced contraction of P epithelium.

CONCLUSION: 6 months of SPHB treatment results in a 32% decrease in prostate tissue levels of DHT (p = 0.005). Thus, SPHB may function in vivo as an inhibitor of 5AR. Compared to the finasteride effect on 5AR (5-fold increase in tissue T and 80% decline in tissue DHT levels), the SPHB effect appears modest.