title: Activity of progesterone and anti-progestins in a rat mammary primary cell culture system.
abstract: A primary culture system of virgin rat mammary epithelial cells, grown in a serum-free medium, was developed as a means of assaying the efficacy of compounds with known anti-progestational properties. Cells were grown in 24-well plates on hydrated collagen gels and could be cultured for at least seven days. Experiments were routinely stopped three days after overnight attachment of cells using fibronectin (4 micrograms/ml). DNA synthesis, measured by thymidine incorporation, was significantly increased by the addition of ovine prolactin (43 nM; P < 0.01) or progesterone (0.15 microM; P < 0.05) or both (P < 0.01) to the basal medium. When added to medium containing progesterone plus prolactin (complete medium), RU486 (mifepristone) and ZK98734 (lilopristone) significantly depressed DNA synthesis in a dose-dependent manner using doses ranging from 0.015 microM to 15 microM. Maximum inhibition was achieved at 15 microM for both compounds. DNA synthesis was 24.5 +/- 2.6% (mean +/- SEM, n = 4) and 32.0 +/- 2.2% (n = 3) of that in complete medium for RU486 and ZK98734, respectively (both P < 0.001). There was no inhibitory effect of either compound in basal medium or basal medium plus prolactin, indicating the absence of toxicity and that the inhibitory effect is specific for a progesterone-mediated process.
authors.affiliation: Babraham Institute, Cambridge, UK.
authors.forename: J A
authors.initials: JA
authors.lastname: Taylor
authors.forename: I A
authors.initials: IA
authors.lastname: Forsyth
authors.forename: M W
authors.initials: MW
authors.lastname: Wang
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D003094:Collagen; D003470:Culture Media; D004247:DNA / Q000096:biosynthesis; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects; D004963:Estrenes / Q000494:pharmacology; D005260:Female; D005782:Gels; D006727:Hormone Antagonists / Q000494:pharmacology*; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects*; D015735:Mifepristone / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology*; D011388:Prolactin; D051381:Rats; D017208:Rats, Wistar; D012756:Sheep
chemical_list: D003470:Culture Media; D004963:Estrenes; D005782:Gels; D006727:Hormone Antagonists; D015735:Mifepristone; C048260:lilopristone; D011374:Progesterone; D011388:Prolactin; D003094:Collagen; D004247:DNA