Effect of the sexual steroids and of diethylstylbestrol on the respiration of yeast

Abstract

A study has been made of the action of the sexual steroids (Testosterone, Progesterone, Estrone and Estradiol) and of Diethylestylbestrol on the respiration of yeast, it being observed that Diethylestylbestrol, especially, produces an intense stimulation of the endogenous respiration and an inhibition of the exogenous respiration with glucose, as had already been described by other authors.

The stimulation of the endogenous respiration becomes inhibition at high concentrations of the estrogen, but thc critical concentration, if the effect is to be inverted, varies with the pH of the incubation medium, probably because with it the degrce of ionization of the product and the speed of penctration into the cells also vary.

The inhibition of the exogenous respiration is accompanied by a parallel inhibition of the intake of glucose by the cells. In the hemogenate of yeast, however, Diethylestylbestrol does not produce inhibition, but rather stimulates both eudogenous and exogenous respiration, and does not inhibit the consumptiou of glucose. These facts suggest that the inhibition of the exogenous respiration in the intact cells is clue to an inhibition of the transport of glucose by the cellular membrane. Diethylestylbestrol makes the Crabtree effect disappear in the homogenate of yeast in exactly the same way as do the disconnecting agents. Thus the stimulation of the endogenous respiration might, in fact, be due to oxidizing phosphorilation, as has been previously suggested by other authors.