Analysis of purines.

The fact that purine nucleotides and nucleosides are so important in normal cellular functions makes their analysis complicated. In order to measure tissue levels, samples have to be very rapidly fixed. Measurement in blood is complicated by the risk of releasing purine nucleotides during the sampling procedure and by the possibility of very rapid inactivation by cellular mechanisms as well as extracellular enzymes. Dialysis probes may offer a possibility of sampling extracellular fluid, but the trauma of placing the dialysis fibre can in itself provide a major stimulus for purine release. Once an adequate sample is taken, there are several methods for the actual quantitation, but most commonly various HLPC procedures are used.