Urinary Excretion of Oligosaccharides Induced by Galactose Given Orally or Intravenously

Abstract

The effect of oral administration of galactose, lactose and sucrose and i.v. injection of galactose on the urinary excretion of blood-group-active oligosaccharides was studied. Galactose given as the free sugar, a glycoside (lactose) or a constituent of normal diet was an absolute requirement for the formation and excretion of A-trisaccharide, B-trisaccharide and 2''-fucosylgalactose in blood group A, B and O(H) secretors, respectively. Great individual variation was seen in the amounts of galactose-dependent oligosaccharides excreted. Injection of galactose resulted in excretion of 3-59% of the amount of oligosaccharide formed after oral administration to the same individual. The mean ratio A-trisaccharide/B-trisaccharide was 2.7 in 4 blood-group-A1B secretors and 0.22 in 3 A2B secretors and can serve as a parameter for chemical differentiation between the 2 blood groups. The excretion of larger blood-group-active oligosaccharides including the A-pentasaccharide, the B-pentasaccharide and lactodifucotetraose that are normal components in urine from starved A, B and H secretors, respectively, was about the same after oral administration of galactose or lactose. The B-trisaccharide was the only oligosaccharide detected in plasma after oral galactose administration to a blood-group-B secretor individual. The concentration was 0.38 mg/l of plasma.