title: Women with acute intermittent porphyria have a defect in 5α-steroid production during the menstrual cycle.
abstract: OBJECTIVE
  To measure serum concentrations of progesterone, estradiol and 5α- and 5β-reduced progesterone metabolites in the follicular and luteal phases of the menstrual cycle in women with latent acute intermittent porphyria and manifest acute intermittent porphyria in comparison with healthy control women.
  
  
  METHODS
  A descriptive study with repeated measurements during a complete, ovulatory menstrual cycle.
  
  
  METHODS
  University hospital out-patient clinic.
  
  
  METHODS
  Thirty-two women with DNA-diagnosed acute intermittent porphyria and 20 healthy control women.
  
  
  METHODS
  Blood samples for serum progesterone, estradiol, allopregnanolone and pregnanolone were drawn on predefined menstrual cycle days, twice in the follicular phase and three times in the luteal phase. Serum levels of estradiol and progesterone were analysed with commercial kits. Allopregnanolone and pregnanolone levels were analysed with radioimmunoassay following diethylether extraction and celite column chromatography.
  
  
  METHODS
  Changes in serum levels of progesterone, estradiol, allopregnanolone and pregnanolone throughout the menstrual cycle.
  
  
  RESULTS
  Women with acute intermittent porphyria displayed lower serum concentrations of allopregnanolone in comparison with healthy control women, the difference being most prominent in the luteal phase (p < 0.001). Levels of pregnanolone did not differ significantly between groups. No significant difference was found between women with latent acute intermittent porphyria and manifest acute intermittent porphyria.
  
  
  CONCLUSIONS
  Decreased levels of the 5α-reduced progesterone metabolite allopregnanolone were found in the menstrual cycle of women with acute intermittent porphyria. This has not been reported previously and could indicate a reduced 5α-reductase type 1 capacity in the ovary and liver among these women.
authors.affiliation: Department of Clinical Science, Obstetrics and Gynecology, Umeå University, Umeå, Sweden. eva.innala@vll.se
authors.forename: Eva
authors.initials: E
authors.lastname: Innala
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Bäckström
authors.forename: Inger Sundström
authors.initials: IS
authors.lastname: Poromaa
authors.forename: Christer
authors.initials: C
authors.lastname: Andersson
authors.forename: Marie
authors.initials: M
authors.lastname: Bixo
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000097:blood*; D000328:Adult; D016022:Case-Control Studies; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000097:blood*; D008875:Middle Aged; D017118:Porphyria, Acute Intermittent / Q000097:blood*; D011280:Pregnanolone / Q000097:blood; D011374:Progesterone / Q000097:blood; D018709:Statistics, Nonparametric; D013548:Sweden
chemical_list: D011374:Progesterone; D004958:Estradiol; D011280:Pregnanolone; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase