Comparison of the inhibitory effect of E-prostaglandins in human and rabbit platelet-rich plasma and washed platelets.

1. The anti-aggregatory potency of a number of E-type PGs was compared in human and rabbit platelet-rich plasma (PRP) and washed platelets. The potency of 13,14-dihydro-PGE1 and 5,6-dihydro-PGE3 is significantly higher in human than in rabbit washed platelets, while the potency of 15-keto-13,14-dihydro-PGE1 is higher in rabbit. 2. The potency of PGEs in rabbit PRP is very similar to that of washed platelets, with the exception of 1a,1b-dihomo-PGE2, which is of a significantly lower potency in PRR. 3. In human, 5,6-trans-PGE2, PGE3, and 15-keto-13,14-dihydro-PGE1 are more potent in PRP than in washed platelets. 4. The results indicate that the potency of E-type PGs in human and rabbit platelets is different and plasma can essentially influence the anti-aggregatory effect of PGEs; plasma can either decrease or increase potency.