title: Expression of the retinoic acid-metabolizing enzymes RALDH2 and CYP26b1 during mouse postnatal testis development.
abstract: OBJECTIVE
  To study the expression pattern of the retinoic acid metabolizing enzymes RALDH2 and CYP26b1 during mouse postnatal testis development at both mRNA and protein levels.
  
  
  METHODS
  Real-time polymerase chain reaction and Western blot analysis were performed to determine the relative quantity of RALDH2 and CYP26b1 at both mRNA and protein levels at postnatal day 1, 5, 10, 20, and in adult mice (70 days testes). Testicular localization of RALDH2 and CYP26b1 during mouse postnatal development was examined using immunohistochemistry assay.
  
  
  RESULTS
  Aldh1a2 transcripts and its protein RALDH2 began to increase at postnatal day 10, and remained at a high level through postnatal day 20 to adulthood. Cyp26b1 transcripts and CYP26b1 protein did not change significantly during mouse postnatal testis development. RALDH2 was undetectable in the postnatal 1, 5 and 10 day testes using immunohistochemistry assay. At postnatal day 20 it was detected in pachytene spermatocytes. Robust expression of RALDH2 was restricted in round spermatids in the adult mouse testis. In the developing and adult testis, CYP26b1 protein was confined to the peritubular myoepithelial cells.
  
  
  CONCLUSIONS
  Our results indicate that following birth, the level of retinoic acid in the seminiferous tubules might begin to increase at postnatal day 10, and maintain a high level through postnatal day 20 to adulthood.
authors.affiliation: Department of Histology and Embryology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Jing-Wen
authors.initials: JW
authors.lastname: Wu
authors.forename: Ru-Yao
authors.initials: RY
authors.lastname: Wang
authors.forename: Qiang-Su
authors.initials: QS
authors.lastname: Guo
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D000072516:Retinoic Acid 4-Hydroxylase; D012670:Seminiferous Epithelium / Q000166:cytology / Q000378:metabolism; D012680:Sensitivity and Specificity; D013087:Spermatids / Q000166:cytology / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; C000607081:Cyp26b1 protein, mouse; D000072516:Retinoic Acid 4-Hydroxylase; D000445:Aldehyde Oxidoreductases; C470579:RALDH2 protein, mouse