Characterization and differentiation of peripheral-type benzodiazepine receptors in rat and human prostate.
We have characterized the presence of peripheral-type benzodiazepine receptor in rat and human prostate. [3H] PK 11195, a putative antagonist, showed a greater affinity for this receptor in rat prostate (KD = 1.71 +/- 0.18 nM) than in human (KD = 15.23 +/- 1.20 nM). In human, the peripheral-type benzodiazepine receptor density (Bmax = 13,575 +/- 1,929 fmols/mg) is double that in rat (Bmax = 6,345 +/- 314 fmols/mg). [3H] Ro 5-4864, an agonist, showed a low affinity (KD = 188.38 +/- 16.46 nM) for human peripheral-type benzodiazepine receptor subtype. We did not detect any difference between the population of this receptor in control human prostate and that in hyperplastic specimens. In rat, bound [3H] PK 11195 was partially inhibited by specific ligands of mitochondrial ADP/ATP carrier. This characteristic does not occur in human prostate. A common trait of both rat and human prostate peripheral-type benzodiazepine receptors is the competitive displacement of bound [3H] PK 11195 by nitrendipine and the blockers of the adenosine uptake system.
Camins
A
A
Laboratory of Pharmacology and Pharmacognosy, Faculty of Pharmacy, Univ. of Barcelona, Spain.
Sureda
F X
FX
Pubill
D
D
Camarasa
J
J
Escubedo
E
E
D000818:Animals; D006801:Humans; D007546:Isoquinolines / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000737:chemistry; D011467:Prostate / Q000737:chemistry* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000032:analysis*
D007546:Isoquinolines; D011963:Receptors, GABA-A; C037850:PK 11195