title: The expression of ovine placental lactogen, StAR and progesterone-associated steroidogenic enzymes in placentae of overnourished growing adolescent ewes.
abstract: Overnourishing pregnant adolescent sheep promotes maternal growth but reduces placental mass, lamb birth weight and circulating progesterone. This study aimed to determine whether altered progesterone reflected transcript abundance for StAR (cholesterol transporter) and the steroidogenic enzymes (Cyp11A1, Hsd3b and Cyp17). Circulating and placental expression of ovine placental lactogen (oPL) was also investigated. Adolescent ewes with singleton pregnancies were fed high (H) or moderate (M) nutrient intake diets to restrict or support placental growth. Experiment 1: peripheral progesterone and oPL concentrations were measured in H (n=7) and M (n=6) animals across gestation (days 7-140). Experiment 2: progesterone was measured to mid- (day 81; M: n=11, H: n=13) or late gestation (day 130; M: n=21, H: n=22), placental oPL, StAR and steroidogenic enzymes were measured by qPCR and oPL protein by immunohistochemistry. Experiment 1: in H vs M animals, term placental (P<0.05), total cotyledon (P<0.01) and foetal size (P<0.05) were reduced. Circulating oPL and progesterone were reduced at mid- (P<0.001, P<0.01) and late gestation (P<0.01, P<0.05) and oPL detection was delayed (P<0.01). Experiment 2: placental oPL was not altered by nutrition. In day 81 H animals, progesterone levels were reduced (P<0.001) but not related to placental or foetal size. Moreover, placental steroidogenic enzymes were unaffected. Day 130 progesterone (P<0.001) and Cyp11A1 (P<0.05) were reduced in H animals with intrauterine growth restriction (H+IUGR). Reduced mid-gestation peripheral oPL and progesterone may reflect altered placental differentiation and/or increased hepatic clearance respectively. Restricted placental growth and reduced biosynthesis may account for reduced progesterone in day 130 H+IUGR ewes.
authors.affiliation: School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Sutton Bonington LE12 5RD, UK. richard.lea@nottingham.ac.uk
authors.forename: Richard G
authors.initials: RG
authors.lastname: Lea
authors.forename: Peter
authors.initials: P
authors.lastname: Wooding
authors.forename: Ian
authors.initials: I
authors.lastname: Stewart
authors.forename: Lisa T
authors.initials: LT
authors.lastname: Hannah
authors.forename: Stephen
authors.initials: S
authors.lastname: Morton
authors.forename: Karen
authors.initials: K
authors.lastname: Wallace
authors.forename: Raymond P
authors.initials: RP
authors.lastname: Aitken
authors.forename: John S
authors.initials: JS
authors.lastname: Milne
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Regnault
authors.forename: Russell V
authors.initials: RV
authors.lastname: Anthony
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Wallace
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics; D000375:Aging / Q000502:physiology; D053180:Animal Nutrition Sciences; D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism; D015870:Gene Expression; D005865:Gestational Age; D007150:Immunohistochemistry; D039382:Maternal Nutritional Physiological Phenomena; D023421:Models, Animal; D044343:Overnutrition / Q000378:metabolism*; D010750:Phosphoproteins / Q000097:blood / Q000235:genetics*; D010920:Placenta / Q000737:chemistry / Q000378:metabolism*; D010928:Placental Lactogen / Q000097:blood / Q000235:genetics*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012741:Sexual Maturation / Q000502:physiology; D034561:Sheep, Domestic; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics; D013250:Steroid Hydroxylases / Q000097:blood / Q000235:genetics*; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D010750:Phosphoproteins; D012333:RNA, Messenger; D000098682:Steroidogenic Acute Regulatory Protein; D011374:Progesterone; D010928:Placental Lactogen; D015096:3-Hydroxysteroid Dehydrogenases; D013250:Steroid Hydroxylases; D013254:Steroid 17-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme