Transfer of Histidine and Xylose Across the Placenta and Into the Red Blood Cell and Amniotic Fluids

¹ From the Departments of Pediatrics, and Obstetrics and Gynecology, New York University-Bellevue Medical Center, New York City

The transfer of l-histidine and d-xylose across the placenta and into the red blood cell and amniotic fluids was investigated in the guinea pig to see if a correlation existed that might be adapted to a measure of placental function. There was a rough correlation in the permeability of the red blood cell and the placenta to both substances but it was not constant. Insufficient l-histidine was transferred into the amniotic fluid under the conditions of these experiments to be accurately measured. d-Xylose was demonstrable in the amniotic fluid in relatively low concentrations, but there was no evident relation to placental permeability.