OBJECTIVESTo investigate the androgen receptor (AR) isoforms expression in human benign and malignant prostatic tissues and LNCaP cells.

METHODSUsing high resolution isoelectric focusing (IEF), the different expression of AR isoforms were demosntrated in human benign and malignant prostatic tissues and LNCaP cells.

RESULTSData were obtained from 41 AR-positive BPH, three prostatic cancer specimens, and LNCaP cells. From these materials, three types of AR isoforms were detected with pI values at 6.5, 6.0 and 5.3. In the case of BPH tissues, 15 (36.5%) specimens expressed all the three types of isoforms at pI 6.5, 6.0 and 5.3, and 10 (24.4%) samples contained isoforms at pI 6.5 and 5.3, five (12.2%) samples indicated isoforms at pI 6.5 and 6.0, four (9.8%) showed the isoforms at pI 6.0 and 5.3. Of all the 41 specimens, two (4.9%) and two (4.9%) as well as three (7.3%) denoted the isoforme at pI 6.5, 6.0 and 5.3 respectively. As for three prostatic cancer specimens, one sample showed all the three types of AR isoforms at pI 6.5, 6.0, 5.3, but another specimen expressed at pI 6.5 and 6.0, and only one failed to indicate any types of isoforms. LNCaP cells expressed all three types of AR isoforms at pI 6.5, 6.0 and 5.3. Binding of 3H-dihydrotestosterone to these three types of isoforms was inhibited by the addition of 100-fold excess of DHT and testosterone. No effect of progesterone, oestradiol and diethylstilboestrol on tritiated hormone binding was observed.

CONCLUSIONSThe expression of AR isoforms is different among various patients and different between BPH and LNCaP cells, though no clear explanation could be induced for this. These results suggest the possibility of explaining effective hormonal therapy to prostatic disease in the future.