The effects of a progesterone metabolite, 5β-dihydroprogesterone, on oxytocin receptor binding in human myometrial membranes
The effects of a progesterone metabolite, 5β-dihydroprogesterone, on oxytocin receptor binding in human myometrial membranes
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DOI：
10.1016/s1470-0328(03)02541-2
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发表时间：
2003-06-01
影响因子：
5.8
通讯作者：
Thornton, S
中科院分区：
文献类型：
--
作者：
Astle, S;Khan, RN;Thornton, S
目的确定孕激素代谢产物5 β-二氢孕酮对人子宫肌层膜催产素受体结合和对单个子宫肌层细胞全细胞钙电流的影响。设计人子宫肌层膜和表达人催产素受体的中国仓鼠卵巢细胞的受体结合研究。全细胞膜片钳实验进行了分离的子宫肌层cells.Setting大学研究实验室和大学hospital.Population接受剖腹产手术的患者在任期之前或之后的劳动力onset.Methods子宫肌层活检从妇女接受剖腹产手术。在表达人催产素受体的子宫肌层膜和中国仓鼠卵巢细胞中测定催产素、5 β-二氢孕酮和阿托西班的结合亲和力。5 β-二氢孕酮对内向电流的影响也被确定在离体子宫肌层cells.Main outcome measures Receptor binding affinity and electrophysiological inward current.Results 5 β-二氢孕酮不降低催产素受体结合在子宫肌层膜或中国仓鼠卵巢细胞表达人催产素受体。也没有影响钙电流下的全细胞补丁条件下，在单个子宫肌层细胞。相比之下，阿托西班抑制从分娩前或分娩后采集的样品制备的子宫肌层膜中的结合（Ki分别= 112和108 nM）。阿托西班对催产素受体的亲和力远低于催产素（在分娩前或分娩后采集的样品中Ki分别为5和6 nM），在表达人催产素受体的子宫肌层膜和中国仓鼠卵巢细胞中（对于阿托西班和催产素，Ki = 63 M和1 nM，结论：5 β-二氢孕酮不太可能通过直接作用于催产素受体结合或内向钙电流来调节子宫肌层活动。
Objective To determine the effect of the progesterone metabolite 5beta-dihydroprogesterone on human oxytocin receptor binding in myometrial membranes and on whole-cell calcium current in single myometrial cells.Design Receptor binding studies in human myometrial membranes prepared from biopsies taken before or after the onset of labour and in Chinese hamster ovary cells expressing the human oxytocin receptor. Whole cell patch-clamp experiments were undertaken on isolated myometrial cells.Setting University research laboratories and University hospital.Population Patients undergoing caesarean section at term either prior to or following onset of labour.Methods Myometrial biopsies were taken from women undergoing caesarean section. The binding affinities of oxytocin, 5beta-dihydroprogesterone and atosiban were determined in myometrial membranes and Chinese hamster ovary cells expressing the human oxytocin receptor. The effect of 5beta-dihydroprogesterone on inward current was also determined in isolated myometrial cells.Main outcome measures Receptor binding affinity and electrophysiological inward current.Results 5beta-Dihydroprogesterone did not reduce oxytocin receptor binding in myometrial membranes or Chinese hamster ovary cells expressing the human oxytocin receptor. Nor did it influence calcium current under whole-cell patch conditions in single myometrial cells. In contrast, atosiban inhibited binding in myometrial membranes prepared from samples taken either prior to or following labour (K-i = 112 and 108 nM, respectively). The affinity of atosiban for the oxytocin receptor was much lower than oxytocin (K-i = 5 and 6 nM in samples taken before or after labour, respectively) in myometrial membranes and in Chinese hamster ovary cells expressing the human oxytocin receptor (K-i = 63 M and 1 nM for atosiban and oxytocin, respectively).Conclusions We conclude that 5beta-dihydroprogesterone is unlikely to regulate myometrial activity as a result of a direct effect on oxytocin receptor binding or inward calcium current.