title: Suppression of Serum Prolactin Levels after Sports Concussion with Prompt Resolution Upon Independent Clinical Assessment To Permit Return-to-Play.
abstract: A significant outflow of neurotransmitters and metabolites with associated enhanced cortical excitation occurs after concussive head trauma. Cellular changes in the acute post-injury period cannot be observed directly in humans, and as such, require indirect evidence from systems sufficiently sensitive to central neuronal cellular excitation. Dopamine is a neurotransmitter with numerous targets in the central and peripheral nervous system. Changes to central dopaminergic tone result in reciprocal responses to the level of serum prolactin (PRL). Thus, a concussion may lead to abnormal dopaminergic tone, resulting in dynamic perturbations in the serum PRL concentration. To determine the effect of concussion on serum PRL concentrations, venipuncture was performed in the morning in four male intercollegiate athletes (age, 20 ± 1 years; height, 71 ± 5 inches; weight, 174 ± 21 pounds) within 48 h of concussion and again at 7 and 14 days post-injury. Serum PRL concentrations for each visit were categorized by quartile within the normal range. In all athletes, serum PRL concentrations increased from the lower quartiles in samples obtained closer to the time of injury to the higher quartiles at 14 days post-injury. These serum PRL changes accompanied the resolution of symptoms and the clinical decision to permit return-to-play. It may be postulated that transient augmentation of central dopaminergic tone resulted in inhibition of PRL secretion early after concussion and that disinhibition of PRL release occurred when central dopaminergic tone subsequently returned to baseline levels. This novel observation provides evidence for dopaminergic dysfunction after concussion that may be tracked by determination of serum PRL levels.
authors.affiliation: 1 School of Health and Medical Sciences, Seton Hall University , South Orange, New Jersey.|2 Institute for Advanced Study of Rehabilitation and Sports Science, Seton Hall University , South Orange, New Jersey.|3 VA Rehabilitation, Research, and Development National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center , Bronx, New York.
authors.forename: Michael F
authors.initials: MF
authors.lastname: La Fountaine
authors.affiliation: 4 Department of Athletics, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Michita
authors.initials: M
authors.lastname: Toda
authors.affiliation: 5 Department of Athletics, Seton Hall University , South Orange, New Jersey.
authors.forename: Anthony
authors.initials: A
authors.lastname: Testa
authors.affiliation: 3 VA Rehabilitation, Research, and Development National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center , Bronx, New York.|6 Departments of Medicine and Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai , New York, New York.
authors.forename: William A
authors.initials: WA
authors.lastname: Bauman
mesh_terms: D056352:Athletes; D001265:Athletic Injuries / Q000097:blood* / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood; D001924:Brain Concussion / Q000097:blood* / Q000175:diagnosis; D006801:Humans; D008297:Male; D011388:Prolactin / Q000097:blood*; D000068958:Return to Sport / Q000502:physiology* / Q000639:trends*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D011388:Prolactin
keywords: adult brain injury; head trauma; hypopituitarism