Growth Inhibition of Microorganisms by Thyroid Hormones. ∗

Abstract

Summary

The growth inhibition induced by thyroactive compounds on vit. B₁₂ and non B₁₂-requiring microorganisms was studied. Thyroactive compounds were inactive for the B₁₂-requiring mutant Escherichia coli 113-3, Lactobacillus leichmannii, and Euglena gracilis, and for their non B₁₂-requiring counterparts. Only Ochromonas malhamensis, a B₁₂-requirer, and Ochromonas danica, a non B₁₂-requirer, were inhibited. Vit. B₁₂ overcame the antagonistic action of the thyroid hormones for O. malhamensis, but not for O. danica where reduced glutathione and Tween 85 overcame the growth inhibition.