ADENOSINE(5') OLIGOPHOSPHO-(5') GUANOSINES AND GUANOSINE(5') OLIGOPHOSPHO-(5') GUANOSINES IN HUMAN PLATELETS

We isolated and identified nucleoside(5') oligophospho-(5') nucleoside s containing adenosine and guanosine (Ap(n)G; n = 3-6) as well as digu anosine polyphosphates (Gp(n)G; n = 3-6) in human platelets, For ident ification, UV spectrometry, matrix-assisted laser desorption/ionizatio n, postsource decay matrix-assisted laser desorption/ionization mass s pectrometry, and enzymatic cleavage experiments were used. The adenosi ne(5') oligophospho-(5') guanosines act as vasoconstrictors and growth factors, The diguanosine polyphosphates are potent modulators of grow th in vascular smooth muscle cells, but do not affect vascular tone.