| Abstract: | Prostacyclin (PGI2) is produced in the vessel wall and acts as a vasodilator hormone. Measurement of plasma 6-keto-PGF1 alpha is considered to be an index of PGI2 production. In the present study the effects of aging on the plasma 6-keto-PGF1 alpha levels were studied in 64 normotensive and 48 essential hypertensive males. The subjects were divided into 3 groups, i.e., young (24-39 years), middle-aged (40-55 years) and elderly (over 56 years) groups. Plasma 6-keto-PGF1 alpha was measured by specific radioimmunoassay after silicic acid column chromatographic purification. The 6-keto-PGF1 alpha levels were lower in elderly normotensive males (10.3 +/- 1.4 pg/ml, mean +/- SE, n = 12) than in normotensive young males (15.3 +/- 2.3, n = 30, p less than 0.05). The plasma 6-keto-PGF1 alpha levels in hypertensive elderly males (10.6 +/- 1.3 pg/ml, n = 10) is lower than in hypertensive young males (19.8 +/- 2.2, n = 17, p less than 0.01). These results indicate that the plasma 6-keto-PGF1 alpha levels decreased with age in both normotensive and hypertensive groups. Thus, PGI2 production may decrease with age. |
