Oxytocin Receptors in Human Uterus*

Abstract
[3H]oxytocin ([3H]OT) was bound in vitro to the 20,000 × g particulate fraction prepared from the myometrium of 2 women, 14–16 weeks pregnant. The apparent dissociation constants for oxytocin binding in preparations of the two uteri were 1.99 ± 0.18 (se) × 10−9m (n = 9) and 2.81 ± 0.26 × 10−9m (n = 10), respectively. A single class of binding sites was apparent within the range of OT concentrations examined, 0.6 to 2.2 nm. About 1.8 × 10−13 moles of OT were bound per mg of particulate protein. The competition for [3H]OT binding sites by synthetic analogues of OT was specific: [desamino]OT > [8-valine]OT ⋝ [4-threonine]OT > OT > [8-lysine]vasopressin > desaminotocinol > [4-proline]OT. The OT binding sites appear to be part of the uterine receptor because of their high affinity and ligand specificity.

This publication has 0 references indexed in Scilit: