THE DIURNAL VARIATION OF PLASMA LEVELS AND URINARY EXCRETION OF 17-HYDROXYCORTICOSTEROIDS IN NORMAL SUBJECTS, NIGHT WORKERS AND BLIND SUBJECTS*†

Abstract

Adiurnal rhythm in the plasma levels and urinary excretion of corticosteroids by men has been reported previously. Pincus et al. (2) and Romanoff et al. (3) showed that the rate of urinary excretion of phosphomolybdic acid-reducing lipids and formaldehydogenic lipids was greater during the morning than during the remaining 24-hour period. Using a more specific method of hydrolysis of the urinary corticoid conjugates, Sandberg et al. (4) reported the same type of variation; similar results were also reported by Laidlaw et al. (5). In a study of the normal plasma levels of 17-hydroxycorticosteroids (17-OH-CS) in man, Bliss et al. (6) found that in any single subject, the 8 a.m. values were higher than those found later in the day. We have extended this study to include the entire twenty-four hours, with special emphasis on the night period. Observations were also made in individuals whose pattern of activity and sleep was reversed and in blind persons, in an attempt to determine the effect of activity and the visual perception of light on this diurnal pattern.