title: Gas chromatography-mass spectrometry of androgens in equine ovarian follicles at ultrastructurally defined stages of development. Identification of 19-nortestosterone in follicular fluid.
abstract: Follicular fluid was obtained from equine follicles at different stages of development as determined by ultrastructural study. Gas chromatography-mass spectrometry associated with stable isotope dilution permitted the demonstration of high levels of 4-estrene-3,7-dione and 17 beta-hydroxy-4-estren-3-one, 17 beta-hydroxy-4-estren-3-one levels often being about 10 times higher than those of testosterone. These findings suggest that in the mare ovary, an aromatizing pathway may proceed using these 19-norsteroids as intermediates. As a consequence of this high level of 19-norsteroids, testosterone content may be most often overestimated by RIA. RIA of steroids in follicular fluid should be validated by a reference technique based on gas chromatography-mass spectrometry, associated with stable isotope dilution.
mesh_terms: D000728:Androgens / Q000032:analysis*; D000818:Animals; D002454:Cell Differentiation; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006736:Horses / Q000502:physiology*; D009277:Nandrolone / Q000032:analysis; D006080:Ovarian Follicle / Q000032:analysis* / Q000166:cytology
chemical_list: D000728:Androgens; D009277:Nandrolone