title: Effect of age on sexually dimorphic selenoprotein expression in mice.
abstract: Clinical data suggest that selenium (Se) supplementation decreases disease predisposition and severity and accelerates recovery in a variety of pathologies. Pre-supplementation Se levels and sex represent important determinants of these Se-dependent health effects. Accordingly, we previously reported on sexually dimorphic expression patterns of Se-dependent glutathione peroxidase 1, type I deiodinase, and selenoprotein P in young mice. In the present study we investigated whether these differences vary with age. The strong sexual dimorphic expression of hepatic type I deiodinase that was observed in young mice vanished both at the mRNA and enzyme activity level by 1 year of age. In contrast, the strong sex-specific differences in renal type I deiodinase mRNA expression were sustained with age. Accordingly, deiodinase enzymatic activities differed in male and female kidneys, largely independent of age [average of 6.8 vs. 15.7 pmol/(min mg) in males vs. females]. In parallel, hepatic Se concentrations and glutathione peroxidase activities increased in female mice compared to male littermates, establishing a new sexual dimorphism in liver. Thus, age represents another important modifier of the dynamic sex- and tissue-specific selenoprotein expression patterns. These data highlight again the unique physiological regulatory mechanisms that have evolved to control Se metabolism according to the actual needs of the organism.
authors.affiliation: Institute for Experimental Endocrinology, Charité-University Medicine Berlin, D-10117 Berlin, Germany. lutz.schomburg@charite.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Schomburg
authors.forename: Cornelia
authors.initials: C
authors.lastname: Riese
authors.forename: Kostja
authors.initials: K
authors.lastname: Renko
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schweizer
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D005786:Gene Expression Regulation; D007453:Iodide Peroxidase / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D012333:RNA, Messenger / Q000378:metabolism; D051140:Selenoproteins / Q000235:genetics* / Q000378:metabolism; D012727:Sex Characteristics
chemical_list: D012333:RNA, Messenger; D051140:Selenoproteins; D007453:Iodide Peroxidase; C507436:selenodeiodinase type 1, mouse