Adenosine(5') oligophospho-(5') guanosines and guanosine(5') oligophospho-(5') guanosines in human platelets.

We isolated and identified nucleoside(5') oligophospho-(5') nucleosides containing adenosine and guanosine (ApnG; n = 3-6) as well as diguanosine polyphosphates (GpnG; n = 3-6) in human platelets. For identification, UV spectrometry, matrix-assisted laser desorption/ionization, postsource decay matrix-assisted laser desorption/ionization mass spectrometry, and enzymatic cleavage experiments were used. The adenosine(5') oligophospho-(5') guanosines act as vasoconstrictors and growth factors. The diguanosine polyphosphates are potent modulators of growth in vascular smooth muscle cells, but do not affect vascular tone.