title: Endocrinological study of the dopaminergic regulation of prolactin release in metastatic breast cancer.
abstract: OBJECTIVE
  Prolactin (PRL) may be a growth factor for breast cancer. Abnormally high levels of PRL have been proven to be associated with a poor prognosis in metastatic breast cancer. However, most studies have been limited to the evaluation of basal levels of PRL rather than its response to the classical endocrine dynamic tests. This study was performed to analyse the dynamic secretion of PRL under stimulatory and inhibitory tests in metastatic breast cancer.
  
  
  METHODS
  The study included 10 untreated metastatic breast cancer women, who were evaluated after the classical stimulatory and inhibitory tests for PRL secretion with the antidopaminergic agent Metoclopramide (10 mg iv as a bolus) and with L-dopa, respectively. Serum levels of PRL were measured by RIA before and at subsequent intervals after drug administration. PRL levels were considered to be elevated when they were higher than 25 ng/ml.
  
  
  RESULTS
  Abnormally high basal levels of PRL were seen in 6/10 patients. L-dopa was unable to inhibit PRL secretion, whose mean concentrations paradoxically significantly increased in response to L-dopa, with values comparable to those observed after the classical stimulatory test with metoclopramide.
  
  
  CONCLUSIONS
  This study confirm the existence of hyperprolactinemia associated with metastatic breast cancer. In addition, by showing a paradoxical rise of PRL in response to L-dopa, which inhibits PRL secretion in physiological conditions, this study would suggest that breast cancer-related hyperprolactinemia may depend at least in part on endogenous disease-related neuroendocrine alterations.
authors.affiliation: Divisione di Radioterapia Oncologica, Ospedale San Gerardo, Monza, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Mandalà
authors.forename: P
authors.initials: P
authors.lastname: Lissoni
authors.forename: A
authors.initials: A
authors.lastname: Ardizzoia
authors.forename: S
authors.initials: S
authors.lastname: Barni
authors.forename: F
authors.initials: F
authors.lastname: Rovelli
authors.forename: G
authors.initials: G
authors.lastname: Confalonieri
authors.forename: F
authors.initials: F
authors.lastname: Malugani
authors.forename: C
authors.initials: C
authors.lastname: Moro
authors.forename: G
authors.initials: G
authors.lastname: Fumagalli
authors.forename: L
authors.initials: L
authors.lastname: Giani
authors.forename: G
authors.initials: G
authors.lastname: Tancini
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000097:blood* / Q000473:pathology*; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008787:Metoclopramide / Q000627:therapeutic use*; D008875:Middle Aged; D011388:Prolactin / Q000097:blood* / Q000378:metabolism
chemical_list: D018492:Dopamine Antagonists; D011388:Prolactin; D008787:Metoclopramide; D004298:Dopamine