Concentrations of carotenoids, retinol and alpha-tocopherol in plasma and follicular fluid of women undergoing IVF

BACKGROUND: Carotenoids are transferred into follicular fluid where they might serve as antioxidants and/or as precursors of retinoids which might modulate follicular or oocyte functions. METHODS AND RESULTS: In 77 women undergoing IVF differences between plasma and follicular fluid in the levels of carotenoids, retinol and alpha-tocopherol were evaluated especially with regard to fertilization success. Concentration of total carotenoids, retinol and alpha-tocopherol determined by HPLC in follicular fluid and plasma were 0.06 +/- 0.02 versus 0.56 +/- 0.23 micro mol/l, 1.26 +/- 0.52 versus 1.66 +/- 0.37 micro mol/l and 4.89 +/- 2.13 versus 21.0 +/- 5.7 micro mol/l (mean +/- SD) respectively (P < 0.001 for all). Differences between plasma and follicular fluid were greater for beta-carotene and lycopene (<20% of plasma concentration) than for lutein and zeaxanthin (>40%). Intrafollicular retinol and retinol-binding protein (RBP) levels represented 58 +/- 23% and 60 +/- 19% of plasma level. Similar molar ratios of retinol/RBP were observed. While no differences in the mean values of all components investigated were observed in plasma and follicular fluid between women with and without reproductive success, the variability in the concentration was much greater in follicular fluid obtained from women without reproductive success. CONCLUSIONS: It remains to be elucidated, if this is indicative of a disturbed sieving effect of the blood-follicle barrier with possibly negative consequences for oocyte maturation.