STUDIES ON THE CARBOHYDRATE METABOLISM IN CHORIONIC VILLI OF THE HUMAN PLACENTA.

Abstract

Chemical studies on the metabolism of glucose, fructose and glycogen in human chorionic villi are reported with the following conclusions: 1) In chorionic villi the level of glucose was the mean value between that of the maternal blood and the fetal blood. The level of fructose was three times as high as that in the fetal blood. 2) Chorionic villi convert glucose into fructose. The best conditions for the conversion were as follows: to keep the glucose level at 125mg/dl in the incubation solution, to keep the pH at 7.4, to have the temperature at 37°C, and to perform the experiment under saturated oxygen. The chorionic vim play an important role in the conversion of sugar in the placenta. 3) The rapid trans-portation of glucose in chorionic villi does not occcur through simple diffusion mechanism, but through biological action in connection with the sugar metabolism in chorionic villi. 4) Human full term placentae have stronger activities in decomposing than in synthesizing glycogen. 5) Sugars in chorionic villi are convertible to each other, such as the schema, glycogen_??_glucose_??_fructose, following changes of environmental condition. The anther stresses the existence of a regulation mechanism for the passage of sugar through the placenta. This mechanism might be called the metabolic regulation system.