Tissue effects of saw palmetto and finasteride: use of biopsy cores for in situ quantification of prostatic androgens.
OBJECTIVE
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.
Marks
L S
LS
Urological Sciences Research Foundation, Culver City, California, USA.
Hess
D L
DL
Dorey
F J
FJ
Luz Macairan
M
M
Cruz Santos
P B
PB
Tyler
V E
VE
D000368:Aged; D000726:Androgen Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D001707:Biopsy, Needle / Q000706:statistics & numerical data; D013196:Dihydrotestosterone / Q000032:analysis*; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D018120:Finasteride / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D011467:Prostate / Q000737:chemistry* / Q000187:drug effects* / Q000473:pathology; D011470:Prostatic Hyperplasia / Q000188:drug therapy* / Q000473:pathology; D028024:Serenoa; D013739:Testosterone / Q000032:analysis*; D016896:Treatment Outcome
D000726:Androgen Antagonists; D004791:Enzyme Inhibitors; D010919:Placebos; D010936:Plant Extracts; D013196:Dihydrotestosterone; D013739:Testosterone; D018120:Finasteride; C040972:saw palmetto extract