Influence of embryonic conditioned media upon the endometrial β-adrenergic receptor

The main objective of this study was to evaluate the influence of the products secreted by the human embryo upon the three subtypes of β-AR (β1, β2, β3). Cell cultures were developed using endometrial biopsies, taken on day 7 after ovulation, from four healthy women <35 years of age, with regular cycles and infertility due only to male factors. Embryos from women with a normal uterine cavity and endometrial lining were incubated until they reached the 4-cell stage, before being transferred to their mother's uterus. Culture media for embryo incubation were derived from two groups: (i) embryos that achieved pregnancy, (ii) embryos which failed to implant. Control and experimental endometrial cell culture plates were treated with the two embryo culture media, with or without 10−9 mol/l oestradiol and 10−7 mol/l progesterone for 48 h. Expression of the three subtypes of β-AR was assessed by RT-PCR. β1-AR was expressed in both control and experimental plates; β2-AR was expressed only in plates incubated with embryonic culture media of embryos which achieved pregnancy, in both hormonal conditions, with or without oestradiol and progesterone. β3-AR was not expressed in any condition. Thus secretory products of human embryos may influence gene expression of β2-AR concentrations in the human endometrium, and this subtype of β-AR may be involved in implantation.