title: Luteinizing hormone depletes ascorbic acid in preovulatory follicles.
abstract: OBJECTIVE
  The objective of the present studies was to determine whether luteinizing hormone (LH) depletes ascorbic acid in the preovulatory follicle.
  
  
  METHODS
  Controlled, prospective experimental study.
  
  
  METHODS
  University-based research center.
  
  
  METHODS
  Sprague-Dawley female rats.
  
  
  METHODS
  Follicular growth and ovulation were induced in immature rats by gonadotropin treatment.
  
  
  METHODS
  Analysis of ovary, follicle, and oocyte levels of ascorbic acid by colorimetric analysis and high-pressure liquid chromatography.
  
  
  RESULTS
  Ovarian ascorbic acid was maximally depleted (50%) within 2 h of LH treatment and was sustained for 8 h. Follicle ascorbic acid levels were unchanged 1 h after LH injection but were significantly reduced within 2 h (40%). Incubation of isolated preovulatory follicles for 3 h with hCG or with menadione (a generator of oxygen radicals) reduced ascorbic acid levels. Isolation of cumulus-enclosed or denuded oocytes depleted ascorbic acid to undetectable levels, but follicular ascorbic acid levels were only moderately depleted by isolation and incubation. Accumulation of ascorbic acid by oocytes was significantly enhanced by the presence of intact cumulus cells.
  
  
  CONCLUSIONS
  Elevation of LH and the production of oxygen radicals deplete ascorbic acid in the preovulatory follicle.
authors.affiliation: Reproductive Biology Section, Yale University School of Medicine, New Haven, Connecticut 06520-8063, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Guarnaccia
authors.forename: M
authors.initials: M
authors.lastname: Takami
authors.forename: E E
authors.initials: EE
authors.lastname: Jones
authors.forename: S L
authors.initials: SL
authors.lastname: Preston
authors.forename: H R
authors.initials: HR
authors.lastname: Behrman
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005260:Female; D005498:Follicular Phase / Q000502:physiology*; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000494:pharmacology*; D009865:Oocytes / Q000378:metabolism; D006080:Ovarian Follicle / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014812:Vitamin K / Q000494:pharmacology
chemical_list: D006063:Chorionic Gonadotropin; D014812:Vitamin K; D007986:Luteinizing Hormone; D001205:Ascorbic Acid