title: Transplacental diffusion and blood flow of gravid bovine uterus.
abstract: Electromagnetic blood flow transducers and uterine arterial, uterine venous, umbilical venous, fetal femoral arterial, and fetal femoral venous catheters were implanted in 11 cows on day 161 +/- 4 of gestation. Antipyrine (0.66 M) plus NaCl (0.16 M) dissolved in deuterium oxide (D2O), or H2O, was infused at a constant rate into the fetal femoral vein catheter. Concentrations of antipyrine and D2O in uterine arterial and venous blood and antipyrine in fetal arterial and umbilical venous blood, as well as middle uterine arterial blood flow (electromagnetic transducer), were determined. Antipyrine and D2O gave similar estimates (steady-state diffusion method) of gravid uterine blood flow. In addition, the slope of the regression of D2O on antipyrine estimates was not different (P greater than 0.10) from one. Electromagnetic transducers gave estimates of uterine blood flow that were 32-42% of those obtained with steady-state diffusion but were correlated (P less than 0.05) with estimates obtained by use of both antipyrine and D2O. The transplacental clearance rate of antipyrine was similar (per kg placenta) to that observed in ewes. It was suggested that the maternal and fetal microvasculatures of the bovine placenta could have a concurrent arrangement with vascular shunts or maldistribution of flows, as has been suggested for the ewe.
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000983:Antipyrine; D002417:Cattle; D003903:Deuterium; D017666:Deuterium Oxide; D004058:Diffusion; D055590:Electromagnetic Phenomena; D005260:Female; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D012039:Regional Blood Flow; D014599:Uterus / Q000098:blood supply*; D014867:Water
chemical_list: D014867:Water; D003903:Deuterium; D017666:Deuterium Oxide; D000983:Antipyrine