Characterization of vasoactive intestinal peptide/pituitary adenylate cyclase-activating peptide receptors in human benign hyperplastic prostate.
Vasoactive intestinal peptide (VIP) is an important member of the group of neuropeptides that appears to be involved in the regulation of prostatic growth and function. Here we studied VIP receptors in membranes from human benign hyperplastic prostate. Accordingly to observations in rat prostatic membranes, [125I]VIP binding to human prostatic membranes suggested two classes of binding sites with high Kd = 0.22 nM) and low (Kd = 37.7 nM) affinities. VIP bound in human and rat membrane preparations to a common VIP/pituitary adenylate cyclase-activating peptide (PACAP) receptor, as VIP, PACAP-27, and PACAP-38 were equipotent for competition of [125I]VIP binding. A PACAP-preferring receptor appears to be expressed in human prostate, since [125I]PACAP binding was displaced with more potency by PACAP than by VIP, and a messenger RNA corresponding to type I PACAP receptor was found. Cross-linking experiments suggested a VIP receptor of about 71 kDa in human and 52 kDa in rat prostates. The binding of [125I]VIP to membranes and the labeling of the bands observed after electrophoresis were competitively inhibited by GTP, suggesting the coupling of VIP receptors to a G protein. Moreover, after solubilization and cross-linking, we observed a 120-kDa band that corresponded to the VIP receptor-alpha s association. VIP stimulated adenylyl cyclase activity in a dose-dependent manner, but the potency and/or the efficacy of VIP were lower in all human preparations studied than in rat prostatic membranes. In conclusion, this study clearly demonstrates the expression of VIP/PACAP common receptors associated with alpha s protein in human prostate and suggests that these neuropeptides could play an important and complex role in the physiology and pathophysiology of this human gland.
Solano
R M
RM
Department of Biochemistry and Molecular Biology, University of Alcalá, Alcalá de Henares, Spain.
Carmena
M J
MJ
Carrero
I
I
Cavallaro
S
S
Roman
F
F
Hueso
C
C
Travali
S
S
Lopez-Fraile
N
N
Guijarro
L G
LG
Prieto
J C
JC
D000262:Adenylyl Cyclases / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D017931:DNA Primers; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000378:metabolism* / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D016133:Polymerase Chain Reaction; D011467:Prostate / Q000378:metabolism*; D011468:Prostatectomy; D011470:Prostatic Hyperplasia / Q000378:metabolism* / Q000601:surgery; D012333:RNA, Messenger / Q000096:biosynthesis; D011869:Radioligand Assay; D051381:Rats; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone / Q000096:biosynthesis / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide / Q000096:biosynthesis / Q000378:metabolism*; D014158:Transcription, Genetic; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism* / Q000494:pharmacology
C495401:ADCYAP1 protein, human; C495403:Adcyap1 protein, rat; D017931:DNA Primers; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases