Glycodelin A is expressed differentially in normal human endometrial tissue throughout the menstrual cycle as assessed by immunohistochemistry and in situ hybridization

ObjectiveTo [1] evaluate glycodelin A immunolabeling in normal endometrium with specific monoclonal (mAb) and polyclonal peptide (pAb) antibodies, [2] to assess glycodelin messenger RNA (mRNA) by in situ hybridization, and [3] to conduct deglycosylation experiments to evaluate the recognized epitope of the mAb vs. pAb.DesignRetrospective immunohistochemical analysis.SettingUniversity institute and hospital in Germany.Patient(s)Normal human endometrial tissue from the proliferative (PP), early secretory, and late secretory phases were obtained from patients undergoing surgery for benign diseases.Intervention(s)Generation of a pAb in rabbit, immunohistochemistry, and in situ hybridization.Main Outcome Measure(s)Semiquantitative and computerized analysis.Result(s)A statistically significant increase of the glycodelin A immunolabeling in the late secretory phase compared with PP was demonstrated by using the mAb. Polyclonal-peptide antibody immunolabeling also showed a rise between the PP and late secretory phases, but without statistical significance. In situ hybridization demonstrated a statistically significantly higher mRNA content during the early secretory phase compared with during PP.Conclusion(s)Glycodelin was demonstrated in normal endometrium at the protein and mRNA levels. The mAb may be more useful in assessing glycodelin expression in endometrium, because it probably can bind to glycodelin A–unique glycan structures, in contrast to the peptide pAb. This is of major interest because it may reveal possible structural and functional relationships in different parts of this molecule and elucidate possible functions of this glycoprotein in human endometrial tissue.