[Changes of the microcirculating blood volume in the reproductive axis during estrous cycle of the rats]

The microcirculating blood volume of the hypothalamic-pituitary-ovarian axis in the female rats was measured using radiobiomicrosphere method during the estrous cycle. The blood flow volume of the hypothalamus and the pituitary was not significantly different between each phase of the estrous cycle. The ovarian blood flow volume was the highest in metestrus and the lowest in estrus. The difference between them was significant (P less than 0.02). The uterine blood flow volume was the highest in metestrus and remained at higher level in diestrus and then changed to the lowest in estrus. The values in metestrus and diestrus were significantly higher than that in estrus (P less than 0.01, P less than 0.05, respectively). The blood flow volume of the oviduct in proestrus was significantly lower than that in estrus (P less than 0.05). The above results suggest that the cyclic changes of the blood volume of the ovary, uterus and oviduct are closely related to their functional state and the hormonal changes.