The effect of several inhibitors on the metabolism and transfer of glucose in the human term placenta.

Abstract

The author studied the uptake and metabolism of glucose in the human term placenta in vitro and obtained the following results. (1) Glucose uptake by the placenta app, ared to be approximately proportional to the glucose concentration in the medium, except for its range of from 100mg to 130mg/100ml, while the placental fructose production had its maximum around the glucose concentration of 100mg/100ml, which is near the upper limit of normal human blood sugar. (2) As to the influence of several chemicals on the glucose uptake, the largest increase was caused by phloridzin, and slight increase by monoiodoacetic acid, estradiol and dinitrophenol. A decrease of the glucose uptake was caused by alloxan. Ouabain had hardly any effect on the glucose uptake. As to fructose production, its increase was caused most remarkably by estradiol and slightly by monoiodoacetic acid, and a decrease was caused by ouabain, alloxan, di-nitrophenol and also slightly by phloridzin. (3) From these results the author suggested the lack of direct participation of ouabain-sensitive ATPase in the active transport of glucose in the placenta. On the contrary, the participation of phosphorylation or heaokinase activity was indefinite. These had rather distinct influence on fructose production.