title: Action of hypoxanthine and meiosis-activating sterol on oocyte maturation in the mouse is strain specific.
abstract: Follicular fluid meiosis-activating sterol (FF-MAS) is regarded as an important compound relevant to meiotic resumption in mammalian oocytes. The objective of this study was to investigate the influence of FF-MAS on germinal vesicle breakdown (GVBD) and first polar body (PBI) extrusion with regard to culture conditions, state of the oocyte and mouse strain. Denuded oocytes (DO) and cumulus-enclosed oocytes (CEO) were retrieved from PMSG-primed Quackenbush or C57BL/6J x DBA/2 (C57) mice and cultured for 20 h in alpha-MEM medium under the following conditions: (i) 250 micromol/l dibutyryl cAMP (dbcAMP) +/- EGF, 1 ng/ml or FF-MAS, 20 micromol/l; (ii) 4 mmol/l hypoxanthine (HX) +/- EGF or FF-MAS; (iii) HX + EGF + FF-MAS; and (iv) HX + FF-MAS 5 h priming and subsequent culture with HX + EGF. Oocyte GVBD and PBI emission were recorded and stained with Hoechst 33342. Very limited meiotic inhibition was observed in Quackenbush mice in comparison with C57 mice. FF-MAS promoted maturation in C57 DO and CEO and Quackenbush DO. In Quackenbush DO and CEO and C57 DO a significant increase in atypical PBI extrusion occurred, but not in C57 CEO as well as in EGF-treated Quackenbush CEO primed or co-cultured with FF-MAS. These results support a meiosis resumption function for FF-MAS and suggest that in its presence, the quality of the MII oocytes retrieved appears to be influenced by the strain of the mice, the state of the oocyte and the presence or absence of growth factors in the culture medium.
authors.affiliation: Department of Obstetrics and Gynaecology, Westmead Hospital, New South Wales 2145, University of Sydney, Australia. annemarg@westgate.wh.usyd.edu.au
authors.forename: A M
authors.initials: AM
authors.lastname: Griffin
authors.forename: C
authors.initials: C
authors.lastname: Grondahl
authors.forename: S D
authors.initials: SD
authors.lastname: Fleming
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002782:Cholestenes / Q000494:pharmacology*; D018920:Coculture Techniques; D003563:Cyclic CMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005260:Female; D019271:Hypoxanthine / Q000494:pharmacology*; D008540:Meiosis / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009865:Oocytes / Q000166:cytology / Q000187:drug effects*; D013045:Species Specificity
chemical_list: D002782:Cholestenes; D019271:Hypoxanthine; D003563:Cyclic CMP; D004815:Epidermal Growth Factor; C100324:4,4-dimethylcholesta-8,14,24-trienol; C053441:dibutyryl cyclic-3',5'-cytidine monophosphate