Glomerular filtration.- physiology and pathophysiology.- methods of investigation.- clearance of inulin.- clearance of endogenous creatinine.- plasma concentration of endogenous creatinine.- measurement of GFR by means of radionuclides.- non-routine methods of measurement of GFR under special conditions.- Urea.- physiology and pathophysiology.- methods of investigation.- plasma urea concentration and blood urea nitrogen (BUN).- the urea concentration in the urine.- urinary urea excretion.- renal urea clearance.- fractional urea excretion.- indications for investigation.- Renal plasma and blood flow.- physiology and pathophysiology.- methods of investigation.- measurement of CPah.- renal extraction of PAH.- calculation of the renal vascular resistance.- filtration fraction.- measurement of ERPF on the basis of radionuclides.- slope clearance of 131I-Hippuran.- the evaluation of separate ERPF.- indications for investigation.- Proteinuria.- physiology and pathophysiology.- classification of proteinuria.- methods of investigation.- bedside and laboratory screening methods for proteinuria.- the 24-hour protein excretion.- clearance of individual proteins and investigation of the selectivity of proteinuria.- polymer clearances.- indications for investigation.- Concentrating ability.- physiology and pathophysiology.- methods of investigation.- urinary osmolarity after 36 hr restriction of water intake.- urinary osmolarity after 24 hr restriction of water intake.- urinary osmolarity after 16 hr restriction of water intake.- scatter of Uosm and specific gravity values over 24 hr under conditions of free fluid intake.- urine osmolarity in the newly born and children.- urine osmolarity after VP or dDAVP administration.- tubular reabsorption of solute-free water.- indications for investigation.- Dilution of the urine.- physiology and pathophysiology.- methods of investigation.- simple (“bolus”) water load.- maintained maximal water diuresis.- induction of water diuresis by intravenous infusion of a hypotonic solution.- indications for investigation.- Excretion of osmotically active solutes.- physiology and pathophysiology.- methods of investigation.- excretion of osmotically active solutes per 24 hours.- the osmolar clearance.- the fractional excretion of osmotically active substances.- induced osmotic diuresis.- indications for investigation.- Excretion of potassium.- physiology and pathophysiology.- methods of investigation.- urinary K concentration.- urinary K excretion.- the renal clearance of K.- fractional K excretion.- indications for investigation.- Excretion of sodium.- physiology and pathophysiology.- methods of investigation.- urine Na concentration.- urinary excretion of Na.- the renal clearance of Na.- fractional excretion of Na.- distal Na reabsorption.- indications for investigation.- Excretion of chloride.- physiology and pathophysiology.- methods of investigation.- urinary excretion of Cl.- the renal Cl clearance and fractional excretion of Cl.- distal Cl reabsorption.- indications for investigation.- Excretion of calcium and phosphate.- physiology and pathophysiology.- methods of investigation.- urinary excretion of Ca.- urinary excretion on a normal diet.- urinary excretion on a low Ca intake.- the Ca/Cr ratio in fasting urine samples.- urinary Ca excretion after loading.- serum Ca concentration.- the renal clearance of Ca.- fractional excretion of Ca.- urinary excretion and plasma concentration of phosphates.- maximal tubular reabsorption of phosphates.- indications for investigation.- Acidifying capacity.- physiology and pathophysiology.- methods of investigation.- spontaneous acidification.- rapid amonium chloride test.- acidification test with arginine HCl.- several days with NH4Cl loading.- investigation of the renal bicarbonate threshold and the maximal tubular reabsorption of bicarbonate.- indications for investigation.- Glucose excretion.- physiology and pathophysiology.- methods of investigation.- qualitative demonstration of glucose in the urine.- glucose excretion.- glucose “titration” and the TmG.- indications for investigation.- Uric acid excretion.- physiology and pathophysiology.- methods of investigation.- urinary concentration of uric acid.- urinary excretion of uric acid.- clearance of uric acid.- fractional excretion of uric acid.- indications for investigation.- Amino acids excretion.- physiology and pathophysiology.- methods of investigation.- demonstration of increased cystine excretion.- urinary excretion of alpha-amino-N.- renal clearance of separate amino acids.- fractional excretion of amino acids.- indications for investigation.