title: Is C-26 hydroxylation an evolutionarily conserved steroid inactivation mechanism?
abstract: Sterols are essential components of virtually all higher eukaryotic organisms, though the exact identity of the dominating sterol varies between species, from the C-27 of cholesterol in vertebrates to the C-28 and C-29 sterols of plants and invertebrates. In addition to their role as structural components of cell membranes these sterols are also converted into a variety of biologically active hormones. This conversion generally involves modifications of the basic structure of the sterol by dealkylation, hydroxylation and/or isomerization. Recent studies have demonstrated that irreversible inactivation of both plant and insect hormones is achieved by a specific C-26 hydroxylation. The concept of sterol deactivation by 26-hydroxylation appears to be an example of an evolutionarily conserved mechanism that has persisted despite the widely varying requirements for sterols in the species where it has been detected.
authors.affiliation: Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden. steve.meaney@labmed.ki.se
authors.forename: Steve
authors.initials: S
authors.lastname: Meaney
mesh_terms: D000818:Animals; D005075:Biological Evolution; D006801:Humans; D006888:Hydroxycholesterols / Q000737:chemistry; D006900:Hydroxylation; D008968:Molecular Conformation; D013256:Steroids / Q000737:chemistry / Q000378:metabolism*
chemical_list: D006888:Hydroxycholesterols; D013256:Steroids; C007042:cholest-5-ene-3 beta,26-diol; C007997:25-hydroxycholesterol