In this study, we examined the localization of vascular endothelial growth factor (VEGF) and the changes in VEGF mRNA expression in various regions of the oviduct in fertile women throughout the ovulatory cycle. Oviduct tissue was collected from 22 women undergoing laparoscopic tubal sterilization or hysterectomy for a benign gynecological condition. Oviduct sections were divided into isthmus, ampullary, and infundibular regions. Serial cross sections were analyzed for the presence of VEGF by specific immunohistochemical staining. The mucosal layer was isolated, and a semiquantitative reverse transcription polymerase chain reaction was performed. Immunohistochemical study revealed VEGF in the oviduct luminal epithelium, smooth muscle cells, and blood vessels within the oviduct. VEGF mRNA expression in oviduct was the highest during the periovulatory stage, and the expression in the ampullary and infundibular regions was higher than that in the isthmus. There was a significant positive correlation between serum FSH and LH concentrations and VEGF mRNA expression. There was no significant correlation between serum estradiol and progesterone concentrations and VEGF mRNA expression. These results suggest that VEGF in human oviduct may play an important role related the early reproductive events, which occur predominantly in the ampulla during the periovulatory phase when serum FSH and LH concentrations are high.

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The ratio of the active progesterone receptor B isoform is higher in the ampullary region of the oviduct. Purpose : To examine mRNA expression of progesterone receptor isoforms AB and B in oviduct mucosal tissue during the ovulatory cycle and in the different functional regions of the human oviduct. Methods : The mucosal layer was isolated from human oviduct tissue and semi-quantitative RT-PCR for progesterone isoforms AB and B was performed. The RT-PCR results were verified by immunohistochemistry. Results : The isthmic region showed no mRNA expression of either progesterone receptor isoform while the relative ratio of the B isoform was significantly higher in the ampullary region compared to the fimbrial region. There was a significant increase in the ratio of PRB to PRAB in the ampullary region compared to the fimbrial region in all samples. Conclusions : We found an increase in the relative abundance of the progesterone receptor B isoform in the ampullary region which is the site of fertilization and early embryo cleavage. Our results indicate that progesterone responsive genes are more likely to be activated in the ampullary region of the oviduct due to the difference in PRAB to PRB ratio. Providing support for the hypothesis that progesterone may play a specific role in providing an appropriate environment for sperm capacitation, fertilization and early embryo cleavage.