Washed human platelets were incubated in a modified Ringer's solution, pH 7.1, at 37°C for 1 hr. Intracellular basal levels for glycogen, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), and orthophosphate were 31.1, 2.52, 1.39, 0.36, and 1.2 μmoles/ml of platelets, respectively. Extracellular ATP, ADP, and AMP remained fairly constant and represented 4, 2, and 4% of total adenine nucleotide content. Total adenine nucleotide content remained unchanged during the period of control incubation. Glycogen depletion was 17.8 μmoles/ml at the end of 1 hr; lactate production was 20.7 μmoles/ml per hr. In the presence of glucose, lactate production increased 100%, and glycogen depletion was spared 13%. Approximately 55% of glucose or glycogen fuel was converted to lactate.
Simon Karpatkin, Richard M. Langer