Progesterone suppresses an oxytocin-stimulated signal pathway in COS-7 cells transfected with the oxytocin receptor.

ABSTRACT: The present study was conducted to determine if progesterone (P4) would inhibit oxytocin-stimulated phosphoinositide hydrolysis in COS-7 cells expressing transfected ovine oxytocin receptor (OTR) with little or no nuclear P4 receptor (nPR) protein present. The relative absence of nPR in these cells was confirmed by immunocytochemistry and RT-PCR. To investigate the effects of P4 on oxytocin (OT) signaling, cells were transiently transfected with the ovine OTR. Radioreceptor assay for [(3)H]-OT binding confirmed the presence of a high affinity binding site for OT in transfected cells, while treatment with P4 and GTPgammaS (which uncouples the OTR from the heterotrimeric G-protein) increased the K(d) for OT binding slightly. Cells were then assayed for inositol phosphate hydrolysis 48 h post

SUBMITTER: Bishop CV 

PROVIDER: S-EPMC2630247 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature