title: Biorhythm in the renal excretion of electrolytes and uric acid in healthy subjects.
abstract: The same 8 subjects were investigated twice within 4 months with regard to variations in the renal clearance of uric acid, creatinine, sodium, potassium, chloride and osmolarity. After a 48-hour stabilization period, clearance values were determined at 2-hourly intervals for 12 hours. Food and fluid intake remained the same for the duration of the studies. The calculation of excretory fractions was based on creatinine clearance as an approximate of glomerular filtration rate. With the exception of creatinine clearance, all the variations tended to decrease during the morning and to exhibit distinct increases in the early afternoon. The maximal excretion fraction coincided with maximal clearance values. The following minimal and maximal clearance values were recorded: uric aicd 4,7-12,7 ml/min; creatinine 131-179 ml/min; Na+ 1,1-2,9 ml/min; K+ 6,6-16,5 ml/min; Cl- 1,4-3,5 ml/min; osmolarity 2,6-3,9 ml/min. The excretion fractions varied from 3,3 to 8,0% (uric acid); 0,7 to 1,8% (Na+); 5,4 to 1,08% (K+); 1,0 to 2,2% (Cl-) and 1,7 to 2,3% (osmolarity). The results of this investigation strongly suggest that clinical trials designed to evaluate the influence of drugs on renal clearances should not be conducted without an appropriate control phase.
mesh_terms: D000328:Adult; D001683:Biological Clocks; D004232:Diuretics / Q000008:administration & dosage; D004573:Electrolytes / Q000097:blood / Q000652:urine*; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D014527:Uric Acid / Q000097:blood / Q000652:urine*
chemical_list: D004232:Diuretics; D004573:Electrolytes; D014527:Uric Acid