title: Formation of 20 beta-dihydrosteroids by anaerobic bacteria.
abstract: Cortisol was metabolized to a variety of products, among them small amounts of cortol by fecal flora of humans and rats. A microorganism, Bifidobacterium adolescentis, isolated from both sources, synthesized a 20-hydroxysteroid dehydrogenase which reduced cortisol to 20 beta-dihydrocortisol. The metabolite was reduced to cortol by Clostridium paraputrificum. The 20-hydroxysteroid dehydrogenase showed a wide substrate specificity; it was independent of the 4-ene and the configuration at C3, C-11, C-17 and C-21. Cortol was resistant to any further alteration by human fecal flora, i.e. it is a metabolic end product. As expected, B. adolescentis effectively prevented 21-dehydroxylation of cortisol by Eubacterium lentum.
mesh_terms: D000305:Adrenal Cortex Hormones / Q000378:metabolism*; D000693:Anaerobiosis; D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D003013:Clostridium / Q000378:metabolism; D005051:Eubacterium / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D013058:Mass Spectrometry; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
chemical_list: D000305:Adrenal Cortex Hormones; D006854:Hydrocortisone