Maternal plasma hypoxanthine levels in nonpreeclamptic twin pregnancies.

We have observed that the elevated plasma adenosine levels are associated with hyperuricemia in nonpreeclamptic twin pregnancies. In animal models, extracellular adenosine is taken up by cells to form adenine nucleotides or is degraded to other purine metabolites such as hypoxanthine, which is further metabolized to xanthine and uric acid. In this study, we measured plasma hypoxanthine levels to evaluate the role of adenosine in hyperuricemia among women with twin pregnancies. Maternal blood samples were taken in 13 twin and 20 singleton pregnancies at 35-36 weeks' gestation. The average maternal plasma hypoxanthine level in twin pregnancies was significantly higher than that in singleton pregnancies. In addition, the plasma hypoxanthine levels have positive correlations both with plasma adenosine and serum uric acid levels. Our results support that an increased adenosine is the main factor contributing to hyperuricemia in twin pregnancies.