Structure and expression of a human oxytocin receptor.
Just before the onset of labour, uterine myometrium becomes extremely sensitive to oxytocin, for which it is a primary target tissue, because of a dramatic increase in the number of oxytocin receptors. We report here the structure and expression of the human oxytocin receptor complementary DNA isolated by expression cloning. The encoded receptor is a 388-amino-acid polypeptide with 7 transmembrane domains typical of G protein-coupled receptors. The oxytocin receptor, expressed in Xenopus oocytes, specifically responds to oxytocin and induces an inward membrane current. Messenger RNAs for the receptor are of two sizes, 3.6 kilobases in breast, and 4.4 kilobases in ovary, uterine endometrium and myometrium. The mRNA level in the myometrium is very high at term. We conclude that the increase in receptor number in the myometrium at labour is, at least in part, due to the increase in mRNA.
Kimura
T
T
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Tanizawa
O
O
Mori
K
K
Brownstein
M J
MJ
Okayama
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009215:Myometrium / Q000378:metabolism*; D009865:Oocytes / Q000502:physiology; D010121:Oxytocin / Q000494:pharmacology; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D011945:Receptors, Angiotensin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018045:Receptors, Oxytocin; D012689:Sequence Homology, Nucleic Acid; D014981:Xenopus
D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D018045:Receptors, Oxytocin; D001127:Arginine Vasopressin; D010121:Oxytocin