1. A new experimental system has been used to analyse factors involved in the initiation of atherosclerosis in rats.
2. Arterial fat deposition in the cerebral arteries was affected by blood pressure, serum cholesterol concentrations, strain difference and age, of which high blood pressure was the most important.
3. A genetic factor independent of hypertension was shown to be involved in acute arterial fat deposition in spontaneously hypertensive rats.