Different patterns of renal prostaglandins I2 and E2 in patients with essential hypertension with low to normal or high renin activity.

Objective: Differences in renal synthesis between prostaglandins I2 and E2, and the relationships of the amounts synthesized to renin release were investigated in patients with essential hypertension.

Methods: Of 12 inpatients, six had low to normal plasma renin activity and six had high renin activity. Before and 30 min after intravenous injection of aspirin D,L-lysine (18 mg/kg), abdominal aortic and renal venous plasma was sampled and assayed for renin activity, 6-ketoprostaglandin F1alpha (as an index of prostaglandin I2), and prostaglandin E2.

Results: In patients with low to normal renin activity, mean +/- SD plasma levels of 6-keto-prostaglandin F1alpha were lower in the right and left renal veins (3.6 +/- 1.4 and 4.1 +/- 1.5 pg/ml, respectively) than in the aorta (5.5 +/- 2.0 pg/ml), but in the other patients, the levels in these veins (7.0 +/- 2.4 and 6.5 +/- 1.5 pg/ml) were higher than in the aorta (5.4 +/- 0.9 pg/ml). Plasma prostaglandin E2 levels in both veins were higher than in the aorta in both groups and, at each site, the levels were similar in the two groups. Aspirin suppressed renin release in the patients with high renin activity.

Conclusions: In patients with essential hypertension with low to normal renin activity, either less prostaglandin I2 than prostaglandin E2 is produced in the kidney or else more is metabolized there, and in such patients with high renin activity, the renal synthesis of prostaglandin I2, more than that of prostaglandin E2, seems to be related to the increased renin release.