Nucleotide, nucleoside and purine base concentrations in human placentae.

Nucleotides, nucleosides and purine bases in trichloroacetic acid extracts of freeze clamped samples of human placenta have been measured by high-pressure liquid chromatography. The concentrations of the nucleotides concerned with energy transduction, ATP, ADP and AMP, and especially the energy charge, are stable over periods of ischaemia of 30 min. Concentrations of 14 nucleotides, including UDPAG, GDP Man, UDP and CTP, have now been defined. In addition, the concentrations of hypoxanthine, xanthine, uridine, adenine and inosine are indicated. Concentrations of the vasodilator adenosine are similar to the apparent Michaelis constants of its main metabolizing enzymes adenosine kinase and adenosine deaminase. The availability of 'normal' values of adenine nucleotide concentrations in human placenta should permit the detection of 'placental insufficiency' of energy supply, if this condition exists.