INHIBITION OF A MICROBIAL GLUCOSE-6-PHOSPHATE DEHYDROGENASE BY DIETHYLSTILBESTROL

Abstract

Diethylstilbestrol readily inhibits the reduction of triphosphopyridine nucleotide by a glucose-6-phosphate dehydrogenase prepared from fractionated cell-free extracts of Aerobacter aerogenes. Hexestrol and dienestrol exert a similar influence but the dehydrogenase system was not sensitive to a number of steroids. The degree and extent of inhibition was a function of the diethylstilbestrol concentration. The inhibition could not be reversed by the addition of excess glucose-6-phosphate or triphosphopyridine nucleotide but the suppression could be relieved by the addition of increments of the fractionated extract containing the glucose-6-phosphate dehydrogenase enzyme. Several other enzymes such as isocitrate, alcohol, and malate dehydrogenases were found to be present in the same fraction but reduction of nucleotides by these enzymes was not influenced by the steroids or synthetic estrogen. A tentative hypothesis is that diethylstilbestrol may interact directly with certain enzymes, under specified experimental conditions, thereby regulating the rate of the enzymatic reaction. These findings thus suggest yet another mechanism whereby a synthetic estrogen may regulate intermediary metabolism.