Effects of long-term treatment with Serenoa repens (Permixon) on the concentrations and regional distribution of androgens and epidermal growth factor in benign prostatic hyperplasia.

BACKGROUND: The n-hexane lipido-sterol extract of Serenoa repens (LSESr, Permixon, Pierre Fabre Medicament, Castres, France), a phytotherapeutic agent used in the treatment of benign prostatic hyperplasia (BPH), has a multisite mechanism of action including inhibition of types 1 and 2 5alpha-reductase and competitive binding to androgen receptors in prostatic cells. Here, the response of testosterone (T), dihydrotestosterone (DHT), and epidermal growth factor (EGF) in BPH tissue of patients treated with LSESr (320 mg/day for 3 months) is analyzed. METHODS: BPH samples were sectioned in periurethral, subcapsular, and intermediate regions: in each region T, DHT, and EGF were determined by radioimmunoassay after purification on celite columns or Sep-pak C18 cartridges. RESULTS: In the untreated group, T, DHT, and EGF presented the highest concentrations in the periurethral region (615 +/- 62 (SE) pg/g tissue, 7,317 +/- 551 pg/g tissue, and 20.9 +/- 3.3 ng/g tissue, respectively) with respect to the peripheral subcapsular region (425 +/- 45 pg/g tissue, 4,215 +/- 561 pg/g tissue, and 10.8 +/- 1.4 ng/g tissue, respectively). In the LSESr-treated group, a statistically significant reduction was observed, mainly in the periurethral region of DHT (2,363 +/- 553 pg/g tissue, P < 0.001) and EGF (6.98 +/- 2.48 ng/g tissue, P < 0.01), with increased T values (1,023 +/- 101 pg/g tissue, P < 0.001). CONCLUSIONS: The decrease of DHT and the rise of T in BPH tissue of patients treated with Permixon confirms the capacity of this drug to inhibit in vivo 5alpha-reductase in human pathological prostate. A marked decrease of EGF, associated with DHT reduction, was also observed. These biochemical effects, similar to those obtained with finasteride, are particularly evident in the periurethral region, whose enlargement is responsible for urinary obstruction, with respect to the subcapsular region. A possible speculation is that the preferential reduction of DHT and EGF content in the periurethral region is involved in the clinical improvement of the obstructive symptoms in BPH during LSESr therapy.

Androgen concentrations and their receptors in the periurethral region are higher than those of the subcapsular zone in benign prostatic hyperplasia (BPH).

Benign prostatic hyperplasia (BPH) is an androgen-dependent disease that initially develops in the inner prostate, where the highest concentrations of testosterone (T) and dihydrotestosterone (DHT) are found. In this study, we have evaluated the cytosolic androgen receptors (ARc), the nuclear androgen receptors (ARn), and the concentrations of T, DHT, and 3alpha-androstanediol (3alphaDiol) in BPH tissue to verify the existence of a possible correlation between androgens and their receptor concentrations. Prostatic samples, removed by suprapubic prostatectomy in 15 untreated patients, were sectioned in periurethral, intermediate, and subcapsular zones. Testosterone, DHT, and 3alphaDiol were evaluated by radioimmunoassay after extraction and purification on celite microcolumns, and ARc and ARn were evaluated by means of dextran-coated charcoal method. In total tissue, mean levels of DHT, T, and 3alphaDiol were 2,531+/-308, 260+/-36, and 403+/-35 pg/mg of DNA (mean+/-SE), respectively. Cytosolic androgen receptors, detectable in all cases, were 16+/-2.8 fmol/mg of protein (mean+/-SE), and ARn, detectable in 12 cases, were 108+/-15 fmol/mg of DNA (mean+/-SE). A linear correlation between DHT and 3alphaDiol, T and DHT, and 3alphaDiol and ARn was found. If the different regions are considered, the periurethral zone, site of the primitive BPH nodule, presents the highest levels of androgens and ARn with respect to the other regions. This relative hyperandrogenism may be responsible for the growth-promoting processes of this area, leading to urinary obstruction.