title: Sodium oxybate increases prolactin secretion in narcolepsy patients and healthy controls.
abstract: OBJECTIVE
  Hypocretin deficiency causes narcolepsy and may affect neuroendocrine systems, including TSH, ACTH and LH secretion. Symptoms can be treated effectively with sodium oxybate (SXB) in many patients. This study was performed to compare prolactin (PRL) secretion in patients and matched controls and establish the effect of SXB administration on PRL and sleep in both the groups.
  
  
  METHODS
  Open label intervention. Blood was sampled before and after 5 days of SXB treatment. The study was performed at the Leiden University Medical Centre, Leiden, The Netherlands.
  
  
  METHODS
  Subjects were admitted to the clinical research centre on both occasions.
  
  
  METHODS
  Eight male hypocretin-deficient narcolepsy with cataplexy patients and eight controls matched for sex, age, body mass index, waist-to-hip ratio and fat percentage were enrolled.
  
  
  METHODS
  SXB two times 3 g per night for five consecutive nights.
  
  
  RESULTS
  Patients and controls underwent 24 h blood sampling at 10 min intervals for measurement of PRL concentrations. The PRL concentration time series was analysed with a new deconvolution programme, approximate entropy (ApEn) and Cosinor analysis. Sleep was polygraphically recorded. Basal and pulsatile PRL secretion, as well as pulse regularity and frequency, ApEn and diurnal parameters were similar in patients and controls. SXB treatment caused similar nocturnal increase in PRL secretion, advance of the acrophase and decrease in ApEn in patients and controls. Slow wave sleep was increased to a similar extent in patients and controls.
  
  
  CONCLUSIONS
  This detailed study did not demonstrate altered PRL secretion in hypocretin-deficient narcolepsy patients during the basal state or during SXB administration. Therefore, hypocretin signalling is unlikely to be a regulator of the lactotrophic system.
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, Postal Zone J3-R 151, PO Box 9600, 2300 RC Leiden, The Netherlands. c.e.h.m.donjacour@lumc.nl
authors.forename: Claire E H M
authors.initials: CE
authors.lastname: Donjacour
authors.forename: N Ahmad
authors.initials: NA
authors.lastname: Aziz
authors.forename: Marijke
authors.initials: M
authors.lastname: Frölich
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Roelfsema
authors.forename: Sebastiaan
authors.initials: S
authors.lastname: Overeem
authors.forename: Gert Jan
authors.initials: GJ
authors.lastname: Lammers
authors.forename: Hanno
authors.initials: H
authors.lastname: Pijl
mesh_terms: D000759:Adjuvants, Anesthesia / Q000494:pharmacology / Q000627:therapeutic use*; D000328:Adult; D000818:Animals; D006801:Humans; D008297:Male; D009290:Narcolepsy / Q000097:blood*; D011388:Prolactin / Q000097:blood; D012890:Sleep / Q000187:drug effects; D012978:Sodium Oxybate / Q000494:pharmacology*
chemical_list: D000759:Adjuvants, Anesthesia; D012978:Sodium Oxybate; D011388:Prolactin