24-Hour periodicity of adrenal cortex.

The diurnal rhythm in the urinary excretion of 17-ketosteroids and neutral reducing lipids has been reported by Pincus. 1) On the other hand the diurnal variation of circulating eosinophils in normal subjects has been studied by Rud,2) Bonner3) and others.4) 5) The characteristic feature in diurnal rhythm of urinary steroids is an increase in the morning especially after awakening. Meanwhile the morning fall in circulating eosinophils such as termed"endogenous eosinopenia" and high level during the night time were established. Halberg has studied eagerly on 24-hour periodicity in various bodily functions with special reference to adrenal cortical function. 4) 6) In this paper a quantitative study on 24-hour periodicity in circulating eosinophils and urinary steroids will be presented.