Identification of alpha 1-adrenoceptor subtypes present in the human prostate.
alpha 1-Adrenoceptors (ARs) play an important role in mediating human prostatic smooth muscle contraction. In the present study cDNA fragments covering different domains of 3 alpha 1-AR subtypes (alpha 1b, alpha 1c and alpha 1d) were generated from human prostate by reverse transcription coupled to the polymerase chain reaction (RT-PCR). The reconstituted partial sequence (349 amino acids) of the human prostatic alpha 1c-AR PCR products showed 94% identity at the amino acid level with that of the corresponding region of the cloned bovine brain alpha 1c-AR. Using human alpha 1-AR subtype selective cDNA probes in Northern blot analysis, the co-expression of mRNA transcripts corresponding to alpha 1b-, alpha 1c- and alpha 1d-AR subtypes was detected in 4 different regions (apex, base, periurethra and lateral lobe) of the human prostate. Competitive inhibition experiments of [3H]-prazosin binding to membrane preparations of human prostate revealed that the non-selective alpha 1-subtype antagonist, alfuzosin, produced a monophasic inhibition curve, whereas oxymetazoline produced a 2-component inhibition curve with pKi values of 8.54 and 5.46. The high-affinity alpha 1-AR component of the oxymetazoline inhibition curve was predominant (57%-66%) and showed an affinity for oxymetazoline comparable to that of the alpha 1c-AR subtype. As such our results illustrate the expression of different alpha 1-AR subtypes in human prostate and importantly that alpha 1c represents the predominant alpha 1-AR subtype present in this tissue.
Faure
C
C
Synthélabo Recherche (L.E.R.S.), Bagneux, France.
Pimoule
C
C
Vallancien
G
G
Langer
S Z
SZ
Graham
D
D
D000236:Adenoma / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D017931:DNA Primers; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods; D011224:Prazosin / Q000378:metabolism; D011467:Prostate / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D011869:Radioligand Assay; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000096:biosynthesis* / Q000145:classification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014316:Tritium
D017931:DNA Primers; D012333:RNA, Messenger; D018340:Receptors, Adrenergic, alpha-1; D014316:Tritium; D011224:Prazosin