L-sorbose but not D-tagatose induces hemolysis of dog erythrocytes in vitro

Previous investigations have demonstrated that L-sorbose induces hemolysis of dog erythrocytyes. This effect is probably the consequence of an ATP dep letion of the red blood cells subsequent to inhibition of hexokinase, and t hus the glycolytic pathway, by sorbose 1-phosphate. In the present study, t he susceptibility of dog erythrocytes to D-tagatose, a stereoisomer of L-so rbose, was examined. Washed dog erythrocytes were suspended in Hanks' balan ced salt solution (HBSS, containing 5.6 mM glucose) with or without the add ition of 0.6, 6, and 60 mM L-sorbose or D-tagatose, or in HBSS with total g lucose concentrations of 5.6, 6 and 60 mM D-glucose, After incubation for 2 4 h at 34 degrees C, the suspensions were centrifuged, and the percentage o f hemolysis was determined by measuring the hemoglobin in the sediment and the supernatant. The amount of hemoglobin released in the medium did not di ffer significantly between the control (HBSS) and the test incubations with glucose or D-tagatose supplementation. In contrast, the addition of 6 and 60 mM L-sorbose resulted in significant hemolysis. At the low dose (0.6 mM) , L-sorbose did not have an adverse effect. It is concluded that D-tagatose , unlike L-sorbose, does not have a hemolytic effect on canine erythrocytes . (C) 1999 Academic Press.