Hormonal regulation of oviductal glycoprotein 1 (OVGP1; MUC9) in the rhesus macaque cervix

Background: Macaques are outstanding animal models for the development of new contraceptives. In women, progestin-only contraceptives often fail to block ovulation and are believed to act by altering cervix physiology. Herein, we assessed oviductal glycoprotein 1 (OVGP1) in the macaque cervix as a marker for progestogen action. Materials: Rhesus macaques were treated with estradiol (E₂), E₂ plus progesterone (P), and E₂ plus levonorgestrel (LNG), a contraceptive progestin. Samples consisted of archived blocks of midcervix mucosa (epithelium and lamina propria) and fresh epithelial cells collected non-invasively by cytobrush. OVGP1 was assayed by quantitative real-time PCR and localized by immunocytochemistry. Results: OVGP1 transcript was maximal after E₂ and reduced after treatment with E₂ + P (P <.05). LNG also reduced OVGP1 expression (P <.05). OVGP1-specific staining localized to epithelial cells, and transcript was quantifiable in cytobrush collected samples. Conclusions: OVGP1 expression in cytobrush samples of macaque cervix provides a non-invasive indicator of contraceptive progestin action.