Urinary excretion of a glucose-containing tetrasaccharide. A parameter for increased degradation of glycogen.

The urinary excretion of a glucose-containing oligosaccharide, Glc alpha[1-6Glc alpha[1-4Glc alpha[1-4Glc, (Glc4) has been measured in various physiological and pathological conditions. The Glc4 content of 24 h samples from the same individual was relatively constant, whereas 2 h samples showed up to 4-fold variations in Glc4 concentration. This variation is associated mainly with increased excretion of Glc4 after meals. A carbohydrate-rich diet, starvation or a protein-rich diet, and intense physical activity all affected the urinary excretion of Glc4. Both oral and intravenous administration of glycogen in a Rhesus monkey resulted in increased excretion of Glc4. When Glc4 itself was injected intravenously in small amounts renal clearance was rapid and complete. In contrast, injection of a larger amount resulted in incomplete (approximately 10%) renal clearance, probably due to uptake and metabolism of the oligosaccharide. In patients with glycogen storage diseases, certain malignancies, and pancreatitis, 24 h urinary Glc4 excretion exceeded the normal range. The diagnostic implications of these observations deserve evaluation. The results presented suggest a need for standardization of nutritional status and physical activity when monitoring urinary Glc4 excretion for diagnostic purposes.