INTERNALIZATION AND DISTRIBUTION OF INOSITOL HEXAKISPHOSPHATE IN RED-BLOOD-CELLS

Inositol hexakisphosphate (InsP(6)), an allosteric effector of haemogl obin, is able to modify the oxyhaemoglobin dissociation curve. The rig htwards shift of the curve increases the in vivo oxygen delivery to ti ssues. Such an exogenous substance may be internalized into red blood cells (RBC) using a reversed lysis-resealing process following a hypo- osmotic shock, resulting in InsP(6)-RBC with modified oxygen transport capacity. The efficacy of the process depends on various physicochemi cal parameters which can be fixed during the experimental protocol. Th e variability of InsP(6) internalization from one sample to another ap peared to be mainly due to the natural variation in osmotic fragility of RBC. This factor was also modified during the storage of RBC units before the lysis-resealing process. The separation of InsP(6)-RBC on a density gradient revealed a wide heterogeneity of internalized InsP(6 ) concentration, varying with the degree of osmotic shock. The control of these various parameters will result in resealed InsP(6)-RBC in re producible conditions suitable for in vivo use.