Angiotensin AT(4) receptors in the normal human prostate and benign prostatic hyperplasia.
The cellular localisation and expression of angiotensin AT(4) receptors was examined in the normal human prostate and benign prostatic hyperplasia (BPH) by quantitative in vitro autoradiography using [(125)I]-Ang IV. In the normal human prostate, AT(4) receptors were localised to the glandular epithelium. Interestingly, specific AT(4) receptor binding was significantly reduced in BPH compared to the normal prostate, as quantitated macroscopically (normal: 5038+/-476 dpm/mm(2), n=6 vs BPH: 2701+/-176 dpm/mm(2), n=6, P<0.001) and microscopically (normal: 7.28+/-0.36 grains/mm(2), n=6 vs BPH: 2.50+/-0.47 grains/mm(2), n=6, P<0.001). The findings of the present study demonstrate the presence of AT(4) receptors in the human prostate, being localised to the glandular epithelium, which suggest that the Ang IV/AT(4) system may play a role in the regulation of ionic transport and glandular secretion in the human prostate. The observation that AT(4) receptors appear reduced in BPH suggests that the AT(4) receptor may undergo agonist-induced receptor internalisation, possibly due to increased local tissue levels of Ang IV in BPH.
Dinh
D T
DT
Department of Medicine & Clinical Pharmacology & Therapeutics Unit, Austin & Repatriation Medical Centre, University of Melbourne,. Heidelberg VIC. 3084, Australia.
Frauman
A G
AG
Casley
D J
DJ
Johnston
C I
CI
Fabiani
M E
ME
D001345:Autoradiography; D004847:Epithelial Cells / Q000737:chemistry; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D011467:Prostate / Q000737:chemistry* / Q000166:cytology; D011470:Prostatic Hyperplasia / Q000378:metabolism* / Q000473:pathology; D011485:Protein Binding; D011945:Receptors, Angiotensin / Q000032:analysis / Q000378:metabolism*; D014018:Tissue Distribution
C090830:AT4 receptor; D007457:Iodine Radioisotopes; D011945:Receptors, Angiotensin