title: Norethisterone acetate alters coagulation gene expression in vitro in human cell culture.
abstract: BACKGROUND
  Both oestrogen and progestin and the route of administration have been implicated in cardiovascular and thromboembolic risk in post menopausal hormone users. Transdermal preparations have been reported as safer indicating that liver derived metabolites of oestrogen may be important. The aim of our study was to investigate the in vitro effects of 17β-estradiol, its metabolites, and norethisterone acetate (NETA) on the expression of coagulation genes in cultured human cells.
  
  
  METHODS
  Human hepatocytes and human umbilical vein endothelial cells(HUVECS) were treated with 17β-estradiol, estrone, 2-hydroxyestradiol (2-OH), NETA and NETA/17β-estradiol (10nM) for 24hours. Fibrinogen, factor VII, prothrombin and plasminogen activator inhibitor -1 (PAI-1) mRNA expression was determined in hepatocyte cultures using TaqMan PCR. Tissue factor (TF), tissue factor pathway inhibitor (TFPI), tissue plasminogen activator (tPA) and PAI-1 expression was determined in HUVECS. Expression of estrogen receptors was also determined.
  
  
  RESULTS
  Fibrinogen and factor VII mRNA expression was upregulated 2-4 fold by estradiol and estrone. Addition of NETA downregulated fibrinogen and prothrombin. PAI-1 expression in hepatocytes was upregulated by estrone, 2-OH, NETA and NETA/17β-estradiol. In HUVECS, TF, TFPI and PAI-1 expression was upregulated by estrone but not by 17β-estradiol. NETA upregulated TF, TFPI and tPA expression. Estrogen receptor status was unaffected by the addition of NETA.
  
  
  CONCLUSIONS
  This data suggests a role for progestins in modifying the effects of oestrogen and its metabolites on coagulation gene expression which may contribute to the reduced thrombotic risk associated with transdermal preparations.
authors.affiliation: Coagulation Research Laboratory, Dept of Obstetrics and Gynaecology, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Jeanette F
authors.initials: JF
authors.lastname: Brosnan
authors.forename: Brian L
authors.initials: BL
authors.lastname: Sheppard
authors.forename: L A
authors.initials: LA
authors.lastname: Kelly
authors.forename: John J
authors.initials: JJ
authors.lastname: O'Leary
authors.forename: Lucy A
authors.initials: LA
authors.lastname: Norris
mesh_terms: D001777:Blood Coagulation / Q000187:drug effects* / Q000235:genetics; D002478:Cells, Cultured; D003280:Contraceptives, Oral, Synthetic / Q000494:pharmacology*; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004970:Estrone / Q000494:pharmacology; D005167:Factor VII / Q000235:genetics / Q000378:metabolism; D005340:Fibrinogen / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism; D009640:Norethindrone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000077563:Norethindrone Acetate; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism; D011516:Prothrombin / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011960:Receptors, Estrogen / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013925:Thromboplastin / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000235:genetics / Q000378:metabolism
chemical_list: D003280:Contraceptives, Oral, Synthetic; D008074:Lipoproteins; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D011960:Receptors, Estrogen; C051321:SERPINE1 protein, human; C051928:lipoprotein-associated coagulation inhibitor; D004970:Estrone; D004958:Estradiol; D005167:Factor VII; D011516:Prothrombin; D005340:Fibrinogen; D013925:Thromboplastin; D000077563:Norethindrone Acetate; C001390:2-hydroxyestradiol; D010959:Tissue Plasminogen Activator; D009640:Norethindrone