Labelling of vasopressin and oxytocin receptors from the human uterus.
Four labelled ligands, [3H]arginine vasopressin ([3H]AVP), [3H]oxytocin ([3H]OT), [3H]d(CH2)5[Tyr(Me)2]AVP ([3H]VPA), and [125I]d(CH2)5[Tyr(Me)2-Thr4-Orn8-Tyr(NH2)9]OT([125I]OTA] and nine unlabelled analogues exhibiting enhanced selectivity for rat oxytocin (OT) and vasopressin (VP) receptors were used to characterize OT and VP receptors on myometrial membranes from non-pregnant and pregnant human uteri. On membranes from non-pregnant uteri, [3H]AVP, [3H]VPA, and [125I]OTA labelled with high affinity (Kd values: 3.2, 2 and 0.8 nM, respectively) a major and apparently homogeneous population of sites, the ligand selectivity of which resembled that of rat V1a VP receptors. On membranes from pregnant and non-pregnant uteri, [3H]OT labelled a single population of high-affinity sites that could be distinguished from VP receptors on the basis of ligand selectivity. Several analogues (in particular [125I]OTA) that are highly selective for rat OT receptors exhibited a much less pronounced selectivity for human OT receptors. Experiments with [3H]VPA allowed detection of VP receptors on myometrical membranes from pregnant uteri and confirmed that only OT but not VP receptors increase during pregnancy in humans.
Tence
M
M
Centre CNRS-INSERM de Pharmacologie-Endocrinologie, Montpellier, France.
Guillon
G
G
Bottari
S
S
Jard
S
S
D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D007700:Kinetics; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D009215:Myometrium / Q000187:drug effects / Q000378:metabolism; D010121:Oxytocin / Q000031:analogs & derivatives; D010909:Pituitary Hormones, Posterior; D011247:Pregnancy; D011945:Receptors, Angiotensin / Q000187:drug effects*; D018045:Receptors, Oxytocin; D017483:Receptors, Vasopressin; D014599:Uterus / Q000187:drug effects / Q000378:metabolism*; D014667:Vasopressins
D007457:Iodine Radioisotopes; D010909:Pituitary Hormones, Posterior; D011945:Receptors, Angiotensin; D018045:Receptors, Oxytocin; D017483:Receptors, Vasopressin; D014667:Vasopressins; D010121:Oxytocin