Quantitative analysis of pyridine nucleotides in red blood cells: a single-step extraction procedure.

Quantitative analysis of red cell pyridine nucleotides has been unreliable in the past because of technical problems in extracting them in the presence of hemoglobin. A simple alcoholic extraction procedure for analysis of pyridine nucleotides in red blood cells is described in this paper. Pyridine nucleotides extracted in the presence of hemoglobin in solution show recoveries of NADH, NAD, and NADP averaging over 70%, while recoveries of NADPH were about 60%. In order to show that these techniques could detect actual intracellular differences in nucleotides inside red cells, two experiments were performed in which the ratios of the nucleotides would be predictably altered. Intact cells incubated in the presence of methylene blue show a decrease in the $\text{NADPH}\text{NADP}$ ratio, and intact cells incubated in the presence of hydrazine and lactate show an increase in the $\text{NADH}\text{NAD}$ ratio. The changes in pyridine nucleotide ratios in these experiments are in the expected direction and were easily detected. Levels of pyridine nucleotides in red blood cells of normal human adults are also presented.