Glucose metabolism by human placental villi

Publisher Website
Google Scholar
Abstract
Glucose phosphorylation rates of about 1 [mu] mole/g. / min. have been measured at room temperature in homogenates of human placental chorionic villi, and these rates are relatively constant throughout gestation. This reaction has an apparent Km for glucose of 3 x 10-5 M both in early and term placenta. Human foetal membranes, the amnion and chorion, also phosphorylate glucose at a rate about equal to that of the placenta. On incubation of intact bits of villus tissue from 8-12-week or full-term placenta with labelled pyruvate, followed by paper chromatography of the tissue extract, the following distribution of label was observed: residual pyruvate, 40-60 percent; lactate, 30-50 percent; glucose, 6 percent, fructose, 7 percent; sorbitol, 0.6 percent. The concept of the placenta acting as a foetal liver during early pregnancy is inconsistent with the observation that glucose production by this organ persists up to term.