ThromboxaneA2, as an unstable intermediate between the prostaglandin endoperoxides and thromboxane B2, is a potent inducer of platelet aggregation and causes vasoconstriction.
15(R)-Pinane thromboxaneA2 is the (R)-epimer of pinane thromboxaneA2 . 15(R)-PTA2 does not inhibit collagen-induced platelet aggregation (IC50s = 120-130 μM). It does not affect gastric tone in isolated rat gastric fundus when used at concentrations of 0.5 or 1.5 μg ml and is less effective than PTA2 at inhibiting prostaglandin-induced contraction of isolated rat stomach muscle.