4-Androsten-11β-ol-3,17-dione has been used in platelet aggregation.
Ala-Tyr-Pro-Gly-Lys-Phe-NH2 (AYPGKF- NH2) is a selective, specific proteinase-activated receptor 4 (PAR4) agonist peptide. PAR4 is a G-protein-coupled receptor that is expressed on the surface of human platelets and is involved in the thrombin signaling pathway. Cleavage of PAR4 by the protease thrombin stimulates the receptor and results in signaling of platelet aggregation.
AYPGK is a ligand for the PAR4 receptor; binding results in activation of PAR4. AYPGK stimulates platelet aggregation in vitro (EC50 =15 μM) via PAR4. In human platelets treated with the PAR4 agonist, AYPGKF stimulates the production of thromboxane, a potent agent for platelet-aggregation. Additionally, AYPGKF mediates the thrombin-induced release of endostatin from rat platelets.
