Mechanism of Action of the Gonadal Steroids Producing Diminution of Growth ofStaphylococcus Aureus

摘要

Summary.Studies were undertaken to characterize the mechanism of action of the gonadal steroids responsible for decreasing growth ofStaphylococcus aureus in vitro.Progesterone or testosterone at 20 μg/ml significantly increased the leakage of14C activity from staphylococci pre‐loaded with14C‐glucose. This enhancement of leakage was not detected with Gram negative micro‐organisms. Hormonal diminution of total uptake of alanine was relatively independent of temperature and of the phase of culture. Anaerobiosis increased the steroidal diminution of alanine uptakec.2‐fold. Fraction‐ation of staphylococci following exposure to various14C‐substrates in the presence of progesterone at 40 μg/ml did not reveal any distinctive influences on macromolecular syntheses. Entry of the labels into cellular pools, however, was altered for 8 of the 10 substrates tested. Exchange experiments detailed the effects of steroids on the efflux of internal alanine and lysine. With progesterone at 40 μg/ml, alanine effluxed from the internal pool 3 times as fast as from the corresponding controls. The opposite effect occurred with lysine and progesterone depressed its exit rate. The stepwise removal of cellular constituents indicated a preferential binding of hormones to cell wall components. Using14C‐progesterone or14C‐diethylstilbestrol, 24 and 29, respectively, of the added hormone was firmly bound to mucopeptide preparations, compared to 1–5 bound to whole cells or isolated cell walls. We suggest that the hormones interfere with the integrated functioning of membrane