Vasopressin receptors in human pregnant myometrium and decidua: interactions with oxytocin and vasopressin agonists and antagonists.
Saturation analysis and competition experiments were performed to identify and characterize [3H]arginine vasopressin binding to human myometrium and decidua in late pregnancy. [3H]Arginine vasopressin bound with affinity similar to that of [3H]oxytocin to both tissues (dissociation constant 1 to 2 nmol/L). The concentration of [3H]arginine vasopressin binding sites was high, particularly in decidua, but in all instances was about 50% to 60% of [3H]oxytocin binding. Analogs with selective oxytocic potency (4-threonine oxytocin, isotocin) had high affinity to both [3H]arginine vasopressin and [3H]oxytocin binding sites, as did analogs with both oxytocic and vasopressor activity (vasotocin). Analogs with selective antidiuretic activity (1-deamino-8-D-arginine vasopressin) showed drastically reduced affinity to [3H]oxytocin binding sites and relatively low but significantly higher affinity to [3H]arginine vasopressin binding sites. A new oxytocin antagonist (RW22164 or [1-deamino-2D-tyrosine-(O-ethyl)-4-threonine-8-ornithine]oxytocin) competitively bound to both binding sites. Its affinity to [3H]oxytocin binding sites was greater than to [3H]arginine vasopressin binding sites whereas the relative affinities of a predominantly vasopressor antagonist [Manning compound) were reversed, suggesting the presence of distinct receptors for oxytocin and arginine vasopressin in pregnant human myometrium and decidua.
Ivanisevic
M
M
Department of Obstetrics and Gynecology, Cornell University Medical College, New York, NY 10021.
Behrens
O
O
Helmer
H
H
Demarest
K
K
Fuchs
A R
AR
D000818:Animals; D001127:Arginine Vasopressin / Q000037:antagonists & inhibitors / Q000378:metabolism; D001667:Binding, Competitive; D003656:Decidua / Q000378:metabolism*; D005260:Female; D006801:Humans; D009215:Myometrium / Q000378:metabolism*; D010121:Oxytocin / Q000037:antagonists & inhibitors / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism*; D018045:Receptors, Oxytocin; D017483:Receptors, Vasopressin; D014599:Uterus / Q000378:metabolism; D014668:Vasotocin / Q000031:analogs & derivatives / Q000378:metabolism
D011945:Receptors, Angiotensin; D018045:Receptors, Oxytocin; D017483:Receptors, Vasopressin; C047046:atosiban; D001127:Arginine Vasopressin; D010121:Oxytocin; D014668:Vasotocin