GROWTH REGULATION IN PENICILLIUM PUBERULUM BY ESTRADIOL-17β AND DEOXYCORTICOSTERONE

Abstract

In studies of the effects of steroids on microorganisms a strain of Penicillium puberulum was obtained whose growth in Fries medium was 50% inhibited by 11-deoxycorticosterone (DOC) at a concentration of about 1 [mu]g/ml. This marked effect was specific since small modifications of DOC caused a reduction or loss of its inhibitory activity. The inhibitory effect of DOC was completely abolishedbyestradiol-17[beta], although this latter compound alone afforded only a small stimulation of growth. The action of estradiol-17[beta] was also specific in that small modifications of its structure reduced its DOC-reversing activity. The specificity of the antagonism between DOC and estradiol-17[beta] was indicated by the observation that estradiol reversed the modest inhibition of growth by compounds related to DOC (e.g. DOC-acetate, 14[alpha]-hydroxy DOC), but not inhibition by unrelated compounds (e.g. cholesterol, diethylstilbestrol) or by pH or temperature changes. The action and interaction of DOC and estradiol-17[beta] were concentration dependent, and growth could be regulated by varying the concentration of the steroids in the medium. The possible analogy of these results to interactions between similar steroid hormones in mammals is discussed.