title: Changes in serum free testosterone, sleep patterns, and 5-alpha-reductase type I activity influence changes in sebum excretion in female subjects.
abstract: OBJECTIVE
  Sebum is thought to play an important role in acne vulgaris and sebum excretion rate (SER) is often used as a marker of efficacy in acne studies. This study explored factors that could induce intra-subject variability in SER.
  
  
  METHODS
  SER was measured twice, 7 days apart, on the forehead of 40 healthy subjects. At each visit, the following parameters were also evaluated: serum androgen levels, 5-alpha-reductase type I gene expression, forehead temperature, sleep habits, diet, facial washing routine, and UV exposure.
  
  
  RESULTS
  There was a positive correlation between the time subjects fell asleep on Day 0 and the change in SER for the left (P = 0.010; R = 0.402) and right sides (P = 0.002; R = 0.467) of the forehead. There was a significant inverse correlation between SER and 5-alpha-reductase type 1 expression and between free testosterone levels and 5-alpha-reductase type 1 expression. In sub-analyses performed on men and women, these correlations were only significant for women.
  
  
  CONCLUSIONS
  Variations in sleep patterns, free testosterone, and 5-alpha-reductase type 1 activity are associated with changes in sebum excretion in women. This could explain some of the inter-subject variability in SER measured between visits in clinical studies.
authors.affiliation: Innovaderm Research, Montreal, QC, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Bissonnette
authors.forename: J E
authors.initials: JE
authors.lastname: Risch
authors.forename: K J
authors.initials: KJ
authors.lastname: McElwee
authors.forename: P
authors.initials: P
authors.lastname: Marchessault
authors.forename: C
authors.initials: C
authors.lastname: Bolduc
authors.forename: S
authors.initials: S
authors.lastname: Nigen
authors.forename: C
authors.initials: C
authors.lastname: Maari
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000097:blood*; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D004789:Enzyme Activation; D005260:Female; D005546:Forehead / Q000502:physiology; D006801:Humans; D008297:Male; D012627:Sebaceous Glands / Q000502:physiology*; D012629:Sebum / Q000378:metabolism*; D012727:Sex Characteristics; D012881:Skin Temperature / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology*; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; C476566:steroid-5alpha-reductase type 1
keywords: 5-alpha-reductase 1 gene expression; androgen levels; sebum excretion; sleep patterns