A STUDY ON DIURNAL VARIATION IN URINE EXCRETION

Abstract

In order to investigate diurnal rhythm of urine excretion, 47 patients were studied. The results are summerized as follows:
1) The excretory patterns of urine volume during 24 hours in usual life were classified into five types. They are the nocturnal oliguric type, 9p.m.-3a.m. oliguric type, 0a.m.-6a.m. oliguric type, nocturic type and flat type. The subjects without renal insufficiency showed the nocturic type invariably.
2) In the subjects without renal insufficiency, two excretory patterns of total solute were noticed, the first type with maximum excretion at noon, the second type with maximum excretion in the morning and evening, in contrast with various types of volume.
3) The graphic relation between urine volume and total solute excreted in hourly fraction of urine in usual life clarified the facts that there were two groups independent of types of excretory pattern of volume, one showing a straight line in distribution and the other showing a shift to the right. The total solute in fractions of urine at night was less than that in daytime in each group.
4) Two subjects were kept under a constant water load. From the observation of graphic relation between urine volume and total solute excretion in this experiment, the shift of fractional urine to the right was revealed to be water dieresis.
5) Three subjects were kept under a constant water load and pitressin was injected subcutaneously, and then each subject reached the state of osmotic diuresis in maximum antidiuresis by exogenous ADH.
One subject received constant infusion of 2.5% saline under restriction of water. He represented osmotic diuresis in maximum antidiuresis by endogenous ADH. From the observation of graphic relation between urine volume and total solute excretion in these experiments, straight linear distributions were thought to be chiefly due to osmotic diuresis.
6) In usual life, water diuresis and osmotic diuresis, the rate of Na and total solute excretion into urine was almost constant. From the result that total solute and Na excretion were increased in parallel after administration of hypertonic saline, it is assumed that Na is related to total solute excretion.
From the above results it is thought that diurnal rhythm of urine excretion comes essentially from osmotic diuresis due to diurnal rhythm of total solute excretion but, to some extent, the latter varies with water diuresis.