title: Serum prolactin as a biomarker for the study of intracerebral dopamine effect in adult patients with phenylketonuria: a cross-sectional monocentric study.
abstract: BACKGROUND
  It has been previously postulated that high phenylalanine (Phe) might disturb intracerebral dopamine production, which is the main regulator of prolactin secretion in the pituitary gland. Previously, various associations between Phe and hyperprolactinemia were revealed in studies performed in phenylketonuria (PKU) children and adolescents. The aim of the present study was to clarify whether any relation between serum phenylalanine and prolactin levels can be found in adult PKU patients.
  
  
  METHODS
  We conducted a cross-sectional, monocentric study including 158 adult patients (male n = 68, female n = 90) with PKU. All patients were diagnosed during newborn screening and were treated since birth. Serum Phe, tyrosine (Tyr), prolactin (PRL), and thyroid-stimulating hormone (TSH) levels were measured, and Phe/Tyr ratio was calculated. Males and females were analyzed separately because the serum prolactin level is gender-dependent.
  
  
  RESULTS
  No significant correlations were found between serum phenylalanine, tyrosine, or the Phe/Tyr ratio and serum prolactin level either in the male or in the female group.
  
  
  CONCLUSIONS
  In treated adult PKU patients, the serum prolactin level may not be significantly influenced by Phe or Tyr serum levels.
authors.affiliation: 2nd Department of Medicine, Semmelweis University, Szentkirályi Street 46, Budapest, 1088, Hungary.
authors.forename: Eszter
authors.initials: E
authors.lastname: Juhász
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Bókay J. Street 53, Budapest, 1083, Hungary.
authors.forename: Erika
authors.initials: E
authors.lastname: Kiss
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Bókay J. Street 53, Budapest, 1083, Hungary.
authors.forename: Erika
authors.initials: E
authors.lastname: Simonova
authors.affiliation: Hungarian Academy of Sciences and Semmelweis University "Lendület" Hereditary Endocrine Tumors Research Group, Szentkirályi Street 46, Budapest, 1088, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Patócs
authors.affiliation: 2nd Department of Medicine, Semmelweis University, Szentkirályi Street 46, Budapest, 1088, Hungary. reismann.peter@med.semmelweis-univ.hu.
authors.forename: Peter
authors.initials: P
authors.lastname: Reismann
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood*; D003430:Cross-Sectional Studies; D015259:Dopamine Agents / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010649:Phenylalanine / Q000097:blood*; D010661:Phenylketonurias / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy; D011379:Prognosis; D011388:Prolactin / Q000097:blood*; D014443:Tyrosine / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015259:Dopamine Agents; D014443:Tyrosine; D010649:Phenylalanine; D011388:Prolactin
keywords: Dopamine; PKU; Phenylketonuria; Prolactin