Abstract
Pig platelets contained 0.2 to 2.6 ng. adrenaline/10(8) platelets (4 experiments). Noradrenaline was not detected in them. When platelet-rich plasma was incubated at 37 degrees with 1 or 10mug. of added catechol amine/ml., the platelets continued to accumulate adrenaline for at least 120 min.; only about one-third as much noradrenaline as adrenaline was taken up. The concentrations of adrenaline taken up by different platelet samples at the end of incubation for 90 min. were proportional to the concentration of adenosine triphosphate in the platelets.