Influence of linoleic acid content of the diet on arterial pressure of salt loaded rats. I. Effects on prostaglandin metabolism and sympathetic nervous system.

1. Compared with linoleic acid rich and pellet diet linoleic acid free diet causes an increase in blood pressure in salt loaded rats. The blood pressure increasing effect of linoleic acid poor diet could not be augmented by linoleic acid free diet. 2. The blood pressure was increased by indomethacin in linoleic acid rich and pellet fed rats. In linoleic acid free fed animals indomethacin shows only a brief augmentation of blood pressure. 3. Prostaglandin (PG) biosynthesis was decreased in isolated kidneys and aorta but increased in the kidney medulla homogenate after a four-week linoleic acid free diet. 4.. Chemical sympathectomy by intracerebroventricular injections of 6-hydroxydopamine abolished the blood pressure increasing effect of linoleic acid free diet. We postulate that changes in the PG metabolism and in the activity of sympathetic nervous system are causes for the elevated blood pressure of linoleic acid free fed salt loaded rats and we conclude that the function of the cardiovascular system is influenced favourably by a linoleic acid rich diet.