In the secretory endometria of women, luminal epithelia exhibit gene and protein expressions that differ from those of glandular epithelia.

Objective: To characterize the transcriptome of luminal epithelia (LE) of fertile secretory endometria and compare the results with those from glandular epithelia (GE).

Design: Endometrial samples were collected at 2 and 7 days after initial blood LH surge in separate menstrual cycles. LE were obtained with the use of laser microdissection. mRNA was amplified with the use of linear polymerase chain reaction and hybridized to Agilent 4×44 microarrays. Gene analysis was used to identify differentially expressed mRNAs. Immunohistochemistry was used to assess nine proteins.

Setting: One IVF clinic.

Patient(s): Seven Caucasian fertile cycling women.

Intervention(s): None.

Main Outcome Measure(s): Cycle dating with the use of blood endocrinologic markers, microarrays of laser-microdissected LE, immunohistochemical analysis.

Result(s): One hundred sixty-one (of 401) differentially expressed mRNAs in LE were identified from the metabolism pathway. Increased selective protein expression in LE at 7 days after initial LH surge was observed. LE mRNA expression was the converse of that in GE. The two cell types each had a different significant biologic pathway identified.

Conclusion(s): Our results introduce a new concept that LE differentially expressed mRNAs are in the converse direction to that of GE, indicating different biologic processes despite the GE being continuous with the luminal monolayer. This probable distinction of biologic roles has not been noted previously. Further investigations must take cognizance of this observation.