Age related changes of platelet prostacyclin receptors in humans.

Platelet receptors for PGI2 were investigated in eighteen healthy volunteers divided in two classes of age: nine were 18-40 years old and nine were 41-65 years old. PGI2 platelet receptors were found to decrease significantly with age; the young subjects had 106 +/- 16 (mean +/- SD) high affinity receptors/platelet and 3509 +/- 529 low affinity receptors/platelet whereas the old subjects had 86 +/- 14 high affinity receptors/platelet (P less than 0.02) and 2471 +/- 640 low affinity receptors/platelet (P less than 0.005). The cumulated data from all the subjects yielded a significant negative correlation with age (r = -0.71, P less than 0.001 for the high affinity class and r = -0.65, P less than 0.01 for the low affinity class). The affinity of receptor sites for the ligand did not statistically change with aging (P less than 0.30 and P less than 0.90 respectively for high and low affinity receptors).