VARIATION OF THE TOTAL AMOUNT OF FLUORIDE IN BLOOD OF YOUNG-WOMEN DURING THE MENSTRUAL-CYCLE

We have previously reported the distribution and the forms of fluoride s in the blood of men. This study is concerned with the distribution o f fluorides in the blood of young women and sex-related differences in the fluoride metabolism related to the calcium metabolism keeping the postmenopausal osteoporosis in mind. The present study shows that wom en, aged 18 to 20 years, retain more fluorides in blood compared with men and that the nonionic fluoride level in blood varies during a mens trual cycle, whereas the ionic fluoride level is constant. Since fluor ide has strong affinity for calcium, behavior of fluoride may reflect that of calcium balance during the menstrual cycle. However fluoride w hich binds to calcium is believed to be ionic, Therefore, there must b e a transformation between ionic fluoride and nonionic fluoride in ord er to keep the homeostasis.