Comparative analysis of estradiol-stimulating proteins from four different Dioscorea species

Abstract

BACKGROUND: Dioscorea plants are used in traditional Chinese medicine as a single herbal medicine or formula for relieving menopausal symptoms. We previously isolated an estradiol-stimulating protein, DOI, from the rhizomes of Dioscorea opposite, one of classical Chinese herbal medicines clinically used for treating menopausal symptoms. DOI-like proteins have herein been isolated and characterized from four Dioscorea species, including D. alata (DA), D.hypoglancae (DH), D. opposita (DO), and D. zingiberensis(DZ). OBJECTIVE: Estradiol-stimulating proteins from four Dioscorea spp were isolated and characterized. Their estradiol-stimulating effects and underlying mechanisms regarding estradiol biosynthesis were studied. METHODS: DOI-like proteins from four Dioscorea species, including DA, DZ, DH and DO, have been isolated by DOI-antibody affinity column, and their molecular sizes were determined by native PAGE and SDS-PAGE. Their estradiol-stimulating effects and action mechanisms on ovarian granulosa cells were studied by employing electro-chemiluminescence immunoassay and Western blotting analysis. RESULTS: The DOI-like proteins isolated from four Dioscorea species have molecular weights similar to DOI. The estradiol-stimulating activity of DOI was higher than DOI-like proteins (Fig 1). DOI-like protein up-regulated estrogen-metabolizing enzymes (CYP19 and StAR) and estrogen receptor beta. CONCLUSION: DOI produced an estradiol-stimulating effect on ovarian granulosa cells at least, via up-regulation of estradiol-metabolizing enzymes and estrogen receptor beta, while DOI-like proteins from other Dioscorea spp did not.