title: Comparison of the agonist-antagonist interaction model and the pool model for the effect of remoxipride on prolactin.
abstract: OBJECTIVE
  The tolerance to the prolactin response following administration of antipsychotic drugs has been modelled as a depletion of a prolactin pool (pool model) and a model where the tolerance is explained by a feedback loop including the dopamine interaction of prolactin release (agonist-antagonist interaction model, (AAI model)). The AAI model was superior to the pool model when analyzing data from clinical trials of risperidone and paliperidone. Here we evaluated the two models using the remoxipride data, designed to challenge the short-term prolactin response, from which the original pool model was built.
  
  
  METHODS
  The remoxipride data were collected from a study where eight healthy male subjects received two remoxipride infusions on five occasions. The intervals between the first and second dose on each occasion were 2, 8, 12, 24 and 48 h, respectively. The pool and AAI models were fitted using NONMEM.
  
  
  RESULTS
  According to the objective function values the pool model with a circadian rhythm function fitted the data slightly better, while the AAI model was better in describing the circadian rhythm of prolactin. Visual predictive checks revealed that the models predicted the prolactin profiles equally well.
  
  
  CONCLUSIONS
  According to the analysis performed here, a previous analysis of several clinical studies and literature reports on prolactin concentrations, it appears that the dopamine feedback mechanism included in the AAI model is better than the storage depletion mechanism in the pool model to estimate the bio-rhythm of prolactin time-course and the tolerance development across different populations, drugs, treatment schedules and time.
authors.affiliation: Department of Pharmaceutical Biosciences, Uppsala University, Sweden.
authors.forename: Guangli
authors.initials: G
authors.lastname: Ma
authors.forename: Lena E
authors.initials: LE
authors.lastname: Friberg
authors.forename: Gunilla
authors.initials: G
authors.lastname: Movin-Osswald
authors.forename: Mats O
authors.initials: MO
authors.lastname: Karlsson
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D001800:Blood Specimen Collection / Q000379:methods; D002940:Circadian Rhythm / Q000502:physiology; D018592:Cross-Over Studies; D004334:Drug Administration Schedule; D004347:Drug Interactions / Q000502:physiology; D004361:Drug Tolerance / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011388:Prolactin / Q000037:antagonists & inhibitors / Q000097:blood / Q000187:drug effects*; D017330:Remoxipride / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
chemical_list: D014150:Antipsychotic Agents; D017330:Remoxipride; D011388:Prolactin