UV light-induced changes in washed pig platelets.

The effect of ultraviolet radiation (UV-A, 360 nm) on the thrombin-induced aggregation of washed pig platelets as well as on the release of adenine nucleotides and proteins was studied. The level in platelets of adenine nucleotides, mainly ADP and ATP, decreased rapidly following the exposure of platelets to a high dose of UV-A (0.5 W/cm2, 30 min). Through thrombin-induced aggregation of irradiated platelets was inhibited, the release reaction occurred. The amount of the released adenine nucleotides and proteins was, however, dependent on the dose of UV light. These findings suggest that UV-A light can stimulate the platelet release reaction.