title: Retest reliability of prolactin response to dl-fenfluramine challenge in adults.
abstract: Neuropharmacologic probes to assess central nervous system (CNS) serotonergic responsivity (e.g., dl-fenfluramine) stimulate serotonergic neurotransmission, thereby causing proportional release of pituitary-derived hormones into the circulation. Individual differences in these hormonal responses are thus thought to reflect dimensional variability in central serotonergic activity, which may, in turn, underlie variation in serotonin-related traits of personality (e.g., impulsivity, behavioral inhibition, harm avoidance). However, the long-term temporal stability of neuropharmacologic indices of CNS serotonergic responsivity has not previously been tested in nonpsychiatric patients. dl-Fenfluramine was administered here to 57 adults, aged 24-60 years, on two occasions 6 months apart, to examine the retest reliability of fenfluramine-induced prolactin [PRL] response to fenfluramine. Baseline PRL concentration (i.e., before administration of fenfluramine) was highly stable over the 6 months (r = 0.88). Variability in serotonergic responsivity, adjusted for baseline PRL concentration, age, sex, and drug concentration during the challenge, was moderately reproducible (r = 0.50 for peak DeltaPRL and 0.57 for PRL "area under the curve," p <.0001). These findings are consistent with speculation that variability in indices of central serotonergic function reflects a temporally stable dimension of individual differences.
authors.affiliation: Behavioral Physiology Laboratory, Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260, USA. jdf3@pitt.edu
authors.forename: Janine D
authors.initials: JD
authors.lastname: Flory
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Manuck
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Muldoon
mesh_terms: D000328:Adult; D019540:Area Under Curve; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D005277:Fenfluramine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011388:Prolactin / Q000096:biosynthesis*; D015203:Reproducibility of Results; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*
chemical_list: D008078:Cholesterol, LDL; D005277:Fenfluramine; D011388:Prolactin; D017367:Selective Serotonin Reuptake Inhibitors