The relationship between ascorbic acid, oestradiol 17 beta and progesterone in plasma and in ovaries during the sexual cycle in cattle

This study was carried out to detect the relationships between levels of vi tamin C in plasma, corpus luteum, follicular fluid and those of progesteron e and oestradiol 17 beta in Holstein cows getting through different periods of sexual cycle, presented at slaughterhouse. Prior to slaughter, blood samples from each cow were collected. After slaug hter, ovaries of animals were taken then, the stage of sexual cycle was det ermined post-mortem. Diameters of corpora lutea and follicles were determin ed by ultrasonography. Follicular fluids were aspirated while corpora lutea were incised and weighted. The progesterone and oestradiol 17 beta concent rations were determined by EIA method. Levels of vitamin C were determined by spectrophotometer. Vitamin C concentrations in the corpus luteum were correlated with weights/ diameters of corpora lutea as well as plasma progesterone levels. In additi on, there was also a positive correlation between plasma vitamin C levels a nd diameter of the corpus luteum. Furthermore, a positive correlation was a lso evidenced between plasma progesterone levels and diameter/weight of cor pora lutea. Oestradiol 17 beta levels in follicle fluids increase in parall el with an increase in follicle diameter. On the contrary, small follicles, irrespective of stage of oestrus cycle had, significantly higher vitamin C content than large follicles. In conclusion, it may be speculated that vitamin C might be used in the syn thesis of collagen during formation of the corpus luteum, consumed in incre ased quantities while oestradiol 17 beta biosynthesis occurred.