Some disturbances of erythrocyte metabolism in galactosaemia

Abstract

The nature of the biochemical lesion in galactosemia was studied by comparing the metabolic behavior of the erythrocytes from normal individuals and from cases of the disorder. Galactosemic erythrocytes, in contrast to normal red cells, do not respire on galactose substrates. O2 uptake on glucose substrates is partially inhibited by the presence of galactose. Galactosemic erythrocytes, on exposure to galactose, in vivo or in vitro, accumulate galactose-1-phosphate. Values of up to 20 mg galactose l-phosphate/100 ml blood were obtained. Much smaller amounts accumulate in normal red cells exposed to high galactose concentrations in vitro, and very little galactose-1-phosphate is found in normal infants on a milk diet. After exposure to galactose the O2 uptake of galactosemic erythrocytes is considerably reduced, while that of normal cells is slightly enhanced. This effect is reflected in the level of phosphorylated intermediates: galactose lowers the ester P (other than galactose-1-phosphate) of galactosemic cells and raises that of normal cells. Toxic effect of galactose on blood cells and other tissues is discussed in the light of these findings. Some of the wider implications are touched upon.