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Dopamine receptor expression and function in clinically nonfunctioning pituitary tumors: comparison with the

Rosario Pivonello1, Carmela Matrone, Mariagiovanna Filippella

  • 1Department of Molecular and Clinical Endocrinology and Oncology, Federico II University, Via Sergio Pansini, 5, 80131 Naples, Italy. rpivone@tin.it

The Journal of Clinical Endocrinology and Metabolism
|April 9, 2004
PubMed

Insights

Dopamine D2 receptor expression, particularly the D2short isoform, correlates with cabergoline effectiveness in reducing nonfunctioning pituitary tumor size and alpha-subunit secretion. This suggests cabergoline

Area of Science:

  • Endocrinology
  • Neuroscience
  • Oncology

Background:

  • Clinically nonfunctioning pituitary tumors (NFPTs) often present diagnostic and therapeutic challenges.
  • Dopamine receptor expression is implicated in pituitary tumor growth and hormone secretion.

Purpose of the Study:

  • To investigate the correlation between dopamine receptor and D2 isoform expression and the efficacy of cabergoline treatment in NFPTs.
  • To evaluate cabergoline's effect on alpha-subunit secretion in vitro and tumor mass in vivo.

Main Methods:

  • Tumor samples from 18 patients were analyzed for dopamine receptor and D2 isoform expression using RT-PCR.
  • In vitro functional studies assessed alpha-subunit secretion inhibition.
  • Nine patients with persistent tumors received cabergoline treatment for 1 year, with tumor mass evaluation before and after.

Main Results:

  • Dopamine D2 receptor expression was found in 67% of NFPTs.
  • The D2short isoform was associated with a more favorable response to cabergoline compared to the D2long isoform.
  • Cabergoline treatment resulted in significant tumor shrinkage (56% of patients) and alpha-subunit inhibition (56% of cases), both linked to D2 receptor expression.

Conclusions:

  • Dopamine D2 receptor expression is prevalent in NFPTs and predicts response to cabergoline.
  • The D2short isoform may be a key determinant of cabergoline efficacy in NFPT management.
  • Cabergoline shows therapeutic potential for NFPTs, warranting its consideration in treatment strategies.

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