The circadian rhythms of blood ionized calcium in humans

It is well known that several hormones and minerals develop daily variation in human blood. Recently the presence of circadian rhythms of blood ionized calcium and serum phosphate concentrations in man reported (Science 213: 672-674, 1981). To clarify the difference in race and age, we examined the serum concentration of minerals such as ionized calcium, inorganic phosphate, total calcium and magnesium, and venous blood pH during 24 hours in three 31 to 40 years old Japanese males in good health. Result [1]. There was a correlation between concentration of ionized calcium and blood pH (r = -0.467 p less than 0.001), and between concentration of ionized calcium and total calcium (r = 0.366 p less than 0.005). [2]. Apparent rhythms of ionized calciums and inorganic phosphate concentrations has been noticed.