1. The distribution and metabolism of inositol phospholipids were studied in the erythrocyte membrane of spontaneously hypertensive and normotensive Wistar-Kyoto rats. The incorporation of 32P into these lipids was considered as an index of their turnover, and a reflection of their metabolism.
2. With [γ-32P]ATP as the source of label only the polyphosphoinositides (diphosphoinositide and triphosphoinositide) incorporated 32P. The levels of labelling were lower in hypertensive than in normotensive rats. Our data indicate that, in the hypertensive rats, the kinases responsible for the labelling of polyphosphoinositides exhibited decreased Vmax. for ATP.
3. These changes may be related to those described for calcium binding and transport in the erythrocyte of spontaneously hypertensive rats.