Serum levels of pregnancy-associated endometrial α2-globulin (α2-PEG), a glycosylated β-lactoglobulin homologue, in successful and unsuccessful assisted conception

Abstract

Pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG) is the major secretory protein of the endometrium in the late luteal phase. Serum levels were measured during the implantation period in successful and unsuccessful cycles of assisted conception. The effects of two different treatment regimens were also compared. All patients who underwent ovulation induction therapy showed an endometrial response as measured by a rise in serum levels of alpha 2-PEG. This rise was the same regardless of either implantation or the method of ovulation induction used. Higher levels were seen at oocyte recovery in those cycles treated with clomiphene citrate and may reflect a disordered endometrial response involving a direct effect of the drug on the endometrium. This may explain the difference in success rates in assisted conception when an alternative treatment initially involving down-regulation of endogenous gonadotrophin activity and subsequent administration of gonadotrophins is used. The rise in serum levels seen in pregnancy did not differ statistically according to whether the pregnancy progressed normally or subsequently aborted. Considerably reduced alpha 2-PEG production by the endometrium was identified in one patient who subsequently aborted. The measurement of serum levels of alpha 2-PEG during the implantation phase is unlikely to provide a clinical tool either for early detection of pregnancy or as a prognostic factor of successful implantation.

Glycodelin: A Major Lipocalin Protein of the Reproductive Axis with Diverse Actions in Cell Recognition and Differentiation

“…No differences in midluteal progesterone and late-luteal-phase glycodelin levels have been found between the two groups (179). During pregnancy, the glycodelin serum concentration rises after implantation, but the rise does not differ according to whether pregnancy progresses normally or subsequently miscarries (161).…”

“…Serum glycodelin levels have been measured during the implantation period in successful and unsuccessful cycles, and the effects of two treatment regimens, clomiphene citrate, and pituitary down-regulation and subsequent administration of gonadotropins compared (161). All the patients who underwent superovulation therapy exhibited an endometrial response as indicated by a rise in serum levels of glycodelin.…”

Concentration of endometrial protein PP14 in uterine flushings throughout the menstrual cycle in normal, fertile women

“…The concentration of this protein in plasma has been found to be dependent on progesterone (Joshi et al 1980; Seppala et al 1987; Li et al 1992) as well as on oestrogen (Li et al 1992). It is possible that the concentration of PP14 may reflect endometrial function (Fay et al 1990), although some investigators could not find evidence to support this (Ren et al 1990; Wood et al 1990).…”

Placental Protein 14/Progesterone-Associated Endometrial Protein Revisited

“…The levels of PPM and α2-PEG are lowest at the time of ovulation, then rise during the last week of luteal phase and peak at the onset of menstruation, when the progesterone level has al ready declined. 30,37,38 High levels are maintained for the first days of the following cycle. No similar eleva tion is seen in anovulatory cycles.…”

“…This is suggested by elevated levels in the last week of the menstrual cycle only if the cycle is ovulatory. 7,30,38 The levels are lower if the luteal phase is inadequate. 40 Check and his colleagues 41 studied late luteal phase endometrial biopsies and compared these results with serum PEP levels to evaluate the correlation between the PEP levels and abnormal biopsies and to determine if subnormal PEP levels could be improved by the ther apies used to correct endometrial defects.…”