title: Localisation of 15-hydroxy prostaglandin dehydrogenase (PGDH) and steroidogenic enzymes in the equine placenta.
abstract: 15-hydroxy prostaglandin dehydrogenase (PGDH) is the critical enzyme that determines metabolism of primary prostaglandins. Its expression is determined in part by steroid hormones, particularly progesterone, formed from delta(5) steroids through 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity. To assess whether the regulation of PGDH might occur in a paracrine, autocrine or intracrine fashion, we used immunohistochemistry (IHC) to determine the localisation of key steroidogenic enzymes in the equine placenta and compared these patterns to the distribution of immunoreactive (IR-) PGDH. Placental tissue was obtained from pony or Thoroughbred mares at about Days 150, 250-280 and >300 of pregnancy (term 320 to 360 days; n=5-8 each group). IR-PGDH, 3beta-HSD, cholesterol side chain cleavage enzyme (P450(scc)) and 17-hydroxylase/lyase (P450(C17)) were localised using specific antibodies and the avidin-biotin peroxidase technique and visualised using diaminobenzidine as substrate. IR-P450(scc) was present in trophoblast cells, but not in maternal tissues of the microcotyledons. In contrast, at Days 150 and 280, IR-PGDH was present in maternal epithelial and interstitial cells in the microcotyledons, but was not detected in trophoblast epithelium, chorioallantois or endometrial glands. After Day 300, IR-PGDH was present in the maternal epithelium and interstitial cells of the placenta and it was also present in trophoblast cells in some specimens.
authors.affiliation: Lawson Research Institute, Department of Obstetrics and Gynaecology, University of Western Ontario, London, Canada.
authors.forename: X
authors.initials: X
authors.lastname: Han
authors.forename: P D
authors.initials: PD
authors.lastname: Rossdale
authors.forename: J
authors.initials: J
authors.lastname: Ousey
authors.forename: N
authors.initials: N
authors.lastname: Holdstock
authors.forename: W R
authors.initials: WR
authors.lastname: Allen
authors.forename: M
authors.initials: M
authors.lastname: Silver
authors.forename: A L
authors.initials: AL
authors.lastname: Fowden
authors.forename: A J
authors.initials: AJ
authors.lastname: McGladdery
authors.forename: F
authors.initials: F
authors.lastname: Labrie
authors.forename: A
authors.initials: A
authors.lastname: Belanger
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000032:analysis*; D000446:Aldehyde-Lyases / Q000032:analysis*; D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000032:analysis*; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D004717:Endometrium / Q000166:cytology / Q000201:enzymology; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology; D005260:Female; D006736:Horses / Q000378:metabolism*; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000032:analysis*; D007150:Immunohistochemistry / Q000379:methods; D010920:Placenta / Q000166:cytology / Q000201:enzymology*; D011247:Pregnancy; D013254:Steroid 17-alpha-Hydroxylase; D014327:Trophoblasts / Q000166:cytology / Q000201:enzymology
chemical_list: D003577:Cytochrome P-450 Enzyme System; D015096:3-Hydroxysteroid Dehydrogenases; D006911:Hydroxyprostaglandin Dehydrogenases; C035859:15-hydroxyprostaglandin dehydrogenase; D013254:Steroid 17-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme; D000446:Aldehyde-Lyases