title: [Effect of L-tyrosine on 3beta-HSD activity of rat luteal cells in vitro].
abstract: OBJECTIVE
  To study the effects of L-tyrosine on 3beta-HSD activity of rat luteal cells in vitro.
  
  
  METHODS
  Luteal cells were isolated from ovary tissues of female rats pretreated with PMSG and hCG. Luteal cells were cultured with 95% oxygen and 5% carbon dioxide in 37 degrees C. 3beta-HSD activity was measured by radioimmunoassay (RIA).
  
  
  RESULTS
  (1) 0.2 mmol x L(-1) and 2.0 mmol x L(-1) L-tyrosine significantly inhibited 3beta-HSD activity. (2) 0.2 mmol x L(-1) L-tyrosine exerted different effects on 3beta-HSD activity at different concentrations of pregnenolone (Ph). It increased 3beta-HSD activity at 0.1 micromol x L(-1) and 1 micromol x L(-1) of Pn concentration. With further increase in the concentration of Pn to 100 micromol x L(-1), the stimulating effect of L-tyrosine was switched to suppression effect. (3) L-tyrosine and L-tyrosine hydrazide both inhibited 3beta-HSD activity induced by hCG.
  
  
  CONCLUSIONS
  L-tyrosine affects 3beta-HSD activity of rat luteal cells in vitro. L-tyrosine and tyrosine hydrazide inhibits hCG induced 3beta-HSD activity.
authors.affiliation: Department of Physiology, Zhejiang University School of Medicine, Hangzhou 310031, China.
authors.forename: Hui-ping
authors.initials: HP
authors.lastname: Wang
authors.forename: Jiang
authors.initials: J
authors.lastname: Ni
authors.forename: Zhi-ping
authors.initials: ZP
authors.lastname: Cheng
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D005260:Female; D008184:Luteal Cells / Q000187:drug effects* / Q000201:enzymology; D051381:Rats; D017208:Rats, Wistar; D014443:Tyrosine / Q000494:pharmacology*
chemical_list: D014443:Tyrosine; D015096:3-Hydroxysteroid Dehydrogenases