Endocrine Abstracts

We present an experimental study on human prolactinoma in cell culture from a patient that partially responded to cabergoline treatment and had to have surgical treatment.

Aim: The aim of the study was to assess the effect of cabergoline, dopamine and melatonin on prolactin secretion and cell proliferation in human prolactinoma cell culture from a patient that had transsphenoidal surgery.

Material and methods: Tissue specimen derived from pituitary adenoma fragments removed in routine transsphenoidal surgery. Cells were plated at 10⁵ cells/well into 24-well plate in a final volume of 1 ml. The test substances, cabergoline (CB) in doses between 10⁻⁶–10⁻⁹ M, dopamine (DA) 10⁻⁹ M, melatonin 10⁻⁶ and 10⁻⁹ M or in combination were added and incubated for 4 days. The supernatant was centrifuged and kept frozen until prolactin (PRL) assay. Another 96-well plate was seeded with 10⁴ cells/well for MTT proliferation assay and treated following the same schedule in 0.1 ml/well. Proliferation was assayed by adding 20 μl of 5 mg/ml MTT, incubation 3.5 h in cell incubator, removing media and adding 150 μl MTT solvent (4 mM HCl, 0.1% Nonidet P-40 in isopropanol) and reading absorbance at 590 nm. Prolactin was assayed by electrochemiluminscence with Roche reagents.

Results: Cabergoline significantly inhibited PRL secretion in a dose dependent manner. At 10⁻⁶ M the inhibition was of 59.45%. MLT slightly increased prolactin secretion; dopamine had no effect on PRL secretion. The PRL levels in the samples treated with combination of DA/CB or MLT/CB did not significantly changed compared to the wells treated with CB alone. All tested substances stimulated cell proliferation.

Conclusion: Results confirm the in vivo anti-secretory effect of cabergoline on prolactin without an anti-proliferative effect on tumor cells. Prolactinoma cell culture from transsphenoidal surgery proved to be a good experimental model to test substances that may inhibit tumor growth and to search for specific factors of aggressiveness in the context of personalized medicine.

Note: The study was funded by PNII 41014 research grant.