Subscribe to RSS
Prolactinoma and primary aldosteronism: is there a causal link?
Context: Coincident prolactinoma-APA (aldosterone-producing adenoma) is infrequently reported.
Objective: To identify patients with prolactinoma-APA and test the hypothesis that elevated prolactin (PRL) concentrations play a role in the pathogenesis of primary aldosteronism (PA).
Setting: The study was performed in 2 different referral centres in Munich and Turin
Design: Concomitant prolactinoma-APA was diagnosed on retro- and prospectively recruited PA patients over a 17 – 24 year period. PRLR gene expression levels were determined by oligonucleotide microarrays on 8 APA and 3 NA and real-time PCR on 30 APA and 9 NA. NCI H295R adrenal cells were incubated with 100 nM PRL and CYP11B2 and PRLR gene expression levels were determined by real-time PCR and aldosterone production was quantified by radioimmunoassay.
Results: Seven patients with coincident prolactinoma-APA were identified. A disproportionate number presented with macroprolactinoma (5 out of 7). Mean PRLR gene expression levels in APA were significantly upregulated compared to normal adrenals (1.7-fold, p= 0.006 and 1.5-fold, p= 0.04 by microarray and real-time PCR, respectively) and this difference was independent of gender. In H295R cells, PRL resulted in 1.3-fold increases in both CYP11B2 gene expression (p< 0.001) and aldosterone production (p= 0.01) but had no significant effect on PRLR mRNA levels.
Conclusion: Elevated concentrations of PRL in prolactinoma patients may play a role in APA development in cases of concomitant prolactinoma-APA and elicit elevated CYP11B2 gene expression and aldosterone biosynthesis.