There is evidence from animal studies that 1,25-dihyroxyvitamin D3 (1,25(OH)2D3) is essential for normal reproductive function. Vitamin deficient rats have reduced fertility and VDR null mutant mice demonstrate impaired folliculogenesis. One small uncontrolled study in humans has demonstrated that vitamin D replacement improves menstrual frequency and acne in women with polycystic ovary syndrome (PCOS). We have previously demonstrated that 1,25(OH)2D3 inhibits the production of oestradiol independently of progesterone in luteinised but not in non-luteinised granulosa cells. We have also demonstrated the presence of vitamin D receptors on luteinised granulosa cells and cells of the corpus luteum1.
The aim of this study was to investigate the effect of a range of concentrations of 1,25(OH)2D3 (200picomolar-20nanomolar) on human theca cells dissected from whole ovaries from women with natural cycles undergoing TAH/BSO. Theca was dispersed enzymatically into single cells. Cells were plated at a concentration of 0.5x106 per well in 24 well plates and cultured in McCoys 5A modified medium. Steroid levels were measured in the medium using radioimmunoassay. 1,25(OH)2D3 decreased androstenedione (A) production, p=0.0320 (multiple regression analysis). 1,25(OH)2D3 also decreased A production in the presence of LH (10nanograms per millilitre). 17-hydoxyprogesterone (17OHP) production was unchanged and progesterone (P) production was variable. Where suppression of A production was most significant (p=0.0038), P production was significantly increased in the same wells (p=0.0187).
In summary, 1,25(OH)2D3 inhibited A production from human theca cells, both basally and in the presence of LH. The production of 17OHP was unchanged and of P was variable. This may explain the beneficial action of vitamin D in women with PCOS.
184th Meeting of The Endocrine Society, San Francisco 2002, P2-437
24 - 26 Mar 2003
British Endocrine Societies