title: Effect of a combination oral contraceptive (desogestrel+ethinyl estradiol) on the expression of low-density lipoprotein receptor and its transcription factor (SREBP2) in placental trophoblast cells.
abstract: BACKGROUND
  This in vitro study deals with the effect of a combination oral contraceptive steroid - desogestrel and ethinyl estradiol - on the expression of low-density lipoprotein receptor (LDLR) and its transcription factor (SREBP2) in assessing the functional effectiveness of the LDLR.
  
  
  METHODS
  Differentiated primary placental trophoblast cells isolated from term human placentae and cells from Jar cell line were used for the study. Low-density lipoprotein receptor and SREBP2 expressions were assessed by immunocytochemistry and immunoblot assays with and without combination contraceptive steroid challenge. Functional activity of LDLR was studied by rating the profile of cellular uptake of fluorescent Dil-LDL (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanin perchlorate-LDL). Quantitation of Dil-LDL was done spectrofluorometrically.
  
  
  RESULTS
  Variation of concentration(s) of either of the components of a combination preparation (desogestrel and ethinyl estradiol) showed a comparable change in the expressions of LDLR and SREBP2 to attain their optimal levels. Maximum expression and a significant functional effectiveness were observed at a unique combination of desogestrel (20 ng/mL) and ethinyl estradiol (10 ng/mL).
  
  
  CONCLUSIONS
  The stimulatory effect of a combination contraceptive steroid on LDLR expression is an associated phenomenon of the contraceptive-mediated stimulation of SREBP2 expression.
authors.affiliation: Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
authors.forename: Albina
authors.initials: A
authors.lastname: Arjuman
authors.forename: Hemlata
authors.initials: H
authors.lastname: Pandey
authors.forename: Nimai Chand
authors.initials: NC
authors.lastname: Chandra
mesh_terms: D002460:Cell Line; D002478:Cells, Cultured; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology*; D017135:Desogestrel / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011973:Receptors, LDL / Q000378:metabolism*; D051782:Sterol Regulatory Element Binding Protein 2 / Q000378:metabolism*; D014327:Trophoblasts / Q000187:drug effects* / Q000378:metabolism
chemical_list: D003277:Contraceptives, Oral, Combined; D011973:Receptors, LDL; C497390:SREBF2 protein, human; D051782:Sterol Regulatory Element Binding Protein 2; D004997:Ethinyl Estradiol; D017135:Desogestrel