Characteristic renal excretion patterns in response to physiological,pathological and pharmacological stimuli

• 1.1. The effect of several factors on the renal output of water, sodium, potassium and creatinine, and, in some patients, also of protein and other substances was studied in consecutive 3-h periods under standard conditions. Since the diurnal rhythm cannot be eliminated, the effect of all other factors was evaluated against the background of the large but regular variations of the diurnal excretory rhythm found on control days. It was demonstrated that this elaborate method is indispensable for the study of phenomena of short duration.
• 2.2. The three principal types of physiological diuresis and antidiuresis associated with diurnal rhythm, osmoregulation and circulatory homoeostasis (“volume regulation”) appeared to be characteristic and could be distinguished from each other and from the effect of external agents.
• 3.3. The possible mechanism of the diurnal excretory rhythm is discussed on the basis of differences and similarities in the excretion pattern of several substances. The large parallel variations in sodium and potassium excretion were similarly found in patients with and without significant fluctuations in creatinine output.
• 4.4. A tendency to nycturia could be demonstrated in many patients in spite of continuous bedrest. Nycturia could be attributed to an excessive influence of circulatory homoeostasis overruling the diurnal rhythm. Normal excretory rhythm was always re-established by strict recumbency and inactivity. Patients in whom factors were present favouring an insufficient or an excessive circulation appeared to be prone to nycturia.
• 5.5. The effect of pharmacological doses of hormones was compared with excretion patterns found in endocrine diseases. The excretion pattern was found to be characteristic in Cushing's disease and in glucocorticoid deficiency unaccompanied by miner-alocorticoid deficiency. In the latter condition a non-postural type of nycturia concerning only water output was found.
• 6.6. The effect of ACTH on the renal excretion pattern was shown to be a relatively simple and reliable test for adrenocortical insufficiency.
• 7.7. The characteristic excretion patterns induced by different diuretics are shown. The influence of hyperaldosteronism on the response to diuretics is demonstrated.
• 8.8. Protein excretion varies considerably under the influence of the diurnal rhythm even when the creatinine output shows no appreciable fluctuations. Variations in water and sodium excretion resulting from circulatory homoeostasis or induced by diuretics are only accompanied by changes in protein excretion when creatinine output is appreciably altered. Renal protein output is directly related to variations in the serum albumin concentration.