1. The metabolism of phosphoinositides was investigated in erythrocyte membranes of essential hypertensive patients, normotensive offspring of hypertensive patients and matched controls.
2. Measurement of 32P-labelling of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bis-phosphate revealed no differences in the rate of incorporation of the isotope in essential hypertensive patients compared with controls.
3. In the normotensive offspring of essential hypertensive patients there was a highly significant increase in the rate of 32P incorporation (P < 0.01), compared with matched controls, indicating a higher rate of metabolic turnover in these subjects.
4. These data demonstrate that phosphoinositide metabolism is enhanced in subjects genetically at risk of hypertension, before the blood pressure has risen, but once the blood pressure is established, it is no different from control values. Abnormal phosphoinositide metabolism may be a further manifestation of a genetically determined defect of membrane physicochemical function underlying essential hypertension.