Étude de la glycolyse et de la perméabilité des érythrocytes aux ions orthophosphates dans le rachitisme vitamino-résistant hypophosphatémique héréditaire

Abstract Whole glycolysis, enzymatic activities in the Embden-Meyerhof pathway, kinetics of the penetration of orthophosphate ions, and the concentration of various intracellular fractions, i.e. orthophosphates, intermediate phosphoderivatives of glycolysis and ATP, were studied in 30 normal subjects and in 17 subjects with liereditary hypophosphatemic vitamin D-resistant rickets. A comparison of the results obtained with children treated with vitamin D, those not treated with vitamin D and untreated adults shows no significant differences among the three categories. p]The following results were obtained in our study of affected subjects: 1. 1. Glycolytic activity is elevated without inducing any accumulation of the intermediates between glucose and lactate. 2. 2. Enzymatic activity in the Embden-Meyerhof pathway is normal, except for pyruvate kinase which is significantly increased. 3. 3. The concentration of the intermediate phosphoderivatives of glycolysis is normal. 4. 4. ATP concentration is increased ( P = 0.01). 5. 5. Intracellular orthophosphate concentration is decreased ( P = 0.002). 6. 6. The kinetics of the entrance of extracellular orthophosphates into red blood cells is significantly increased ( P = 0.001) without affecting the final equilibrium of distribution of phosphate ions throughout all parts of the membrane. These results make one think that the hypophosphatemia seen in hereditary vitamin D-resistant rickets cannot be explained either by modification of the plasma membrane permeability to phosphorus or by alteration of glycolysis. The problem of vitamin D resistance and the resultant disturbances which it causes in the cellular transport of calcium are cited as a tentative explanation for