TRANSPORT AND METABOLISM OF ADENOSINE IN DIABETIC HUMAN PLACENTA

Pregnancy complicated by diabetes is a relatively frequent event and m ay result in fetal embriopathy. However, little is known regarding whe ther placental transport functions are altered. In this study, we have compared the activity of the nitrobenzyithioinosine (NBMPR)-sensitive adenosine transporter and adenosine metabolism in human placental bru sh-border- and basal-membrane vesicles from placentas of normal and di abetic pregnancies. Neither [H-3]NBMPR binding, a marker of the facili tative-diffusion nucleoside transporter in the human placenta, nor ade nosine metabolism exhibited a significant difference in either the bru sh-border- or the basal-membrane vesicles between the normal and diabe tic group, except for an increased affinity in [H-3]NBMPR binding at t he basal side in diabetic placenta. This result contrasts with an earl ier finding using the same group of patients that adenosine transport is downregulated in umbilical vein endothelial cells from diabetic pre gnancies. It is concluded that adenosine transport is modulated select ively in different tissues in diabetic pregnancies.