Endocrine Abstracts (2001) 2 P91

PARACRINE STIMULATION OF OVARIAN 11BETA-HYDROXYSTEROID DEHYDROGENASE (11BETA-HSD) ACTIVITY IN HUMAN GRANULOSA-LUTEIN (GL) CELLS BY PROSTAGLANDINS

C Chandras1,2, LM Thurston1,2, DRE Abayasekara2 & AE Michael1,2


1Biochemistry & Molecular Biology, RF&UCMS, University College London, London, UK; 2Reproduction & Development Group, Veterinary Basic Sciences, Royal Veterinary College, London, UK.


In human GL cells, 11beta-HSD catalyses the interconversion of cortisol (F) with its inert 11-ketosteroid metabolite, cortisone (E). Since GL cells synthesise prostaglandins (PGs), and PGs have been shown to modulate the expression and activity of the cloned 11beta-HSD enzymes, the objective of the present study was to establish whether locally synthesised PGs affected the net oxidation of F to E by 11beta-HSD in human GL cells recovered from the ovaries of women undergoing controlled hyperstimulation for assisted conception. Cells (recovered from follicular aspirates with informed patient consent and approval of the Local Ethics Committee) were isolated on 60% Percoll and cultured in vitro at 37 deg C at a density of 50,000 cells/ml in serum-supplemented medium. On day 3 of culture, cells were incubated in serum-free medium containing 100nM [3H]-F plus 0-100microM indomethacin, meclofenamic acid (MA) or niflumic acid (NA). 11beta-HSD activities, quantified over 4h using a standard radiometric conversion assay, were inhibited (by up to 55.0 plus/minus 10.0%, P<0.01) in a concentration-dependent manner by all 3 cyclo-oxygenase inhibitors. In subsequent experiments, 11beta-HSD activities were assessed over 4h in hGL cells co-treated with 1microM MA plus 30nM PGF2alpha, PGD2, PGE2 or butaprost. MA decreased 11beta-HSD activities by 63.9 plus/minus 6.3% (P<0.01) relative to untreated control cells, but this MA-induced suppression was completely reversed by co-treatment with PGF2alpha, PGD2, and butaprost, and could be significantly attentuated by co-treatment with PGE2. We conclude that PGs synthesised in hGL cell cultures exert a paracrine action to maintain high rates of 11beta-HSD-mediated cortisol oxidation which is lost when cells are treated with inhibitors of PG synthesis. (Supported, in part, by Wellcome Trust Project Grant 052970)

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