Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2016, 160(2):238-243 | DOI: 10.5507/bp.2015.058

Expression profiles of somatostatin, dopamine, and estrogen receptors in pituitary adenomas determined by means of synthetic multilocus calibrators

Monika Drastikova^a, Martin Beranek^a,b, Filip Gabalec^c, David Netuka^d, Vaclav Masopust^d, Tomas Cesak^e, Josef Marek^f, Vladimir Palicka^a, Jan Cap^c

^a Institute of Clinical Biochemistry and Diagnostics, Faculty of Medicine in Hradec Kralove, Charles University in Prague and University Hospital Hradec Kralove, Czech Republic

^b Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague

^c 4^th Department of Internal Medicine - Hematology, Faculty of Medicine in Hradec Kralove, Charles University in Prague and University Hospital Hradec Kralove

^d Department of Neurosurgery, 1^st Faculty of Medicine, Charles University in Prague and Central Military Hospital Prague

^e Department of Neurosurgery, Faculty of Medicine in Hradec Kralove, Charles University in Prague and University Hospital Hradec Kralove

^f 3^rd Department of Internal Medicine, 1^st Faculty of Medicine, Charles University in Prague

Aims: Pituitary adenomas (PA) are non-invasive benign tumors with a high autopsy prevalence. They are classified according to the type of hormone secreted (prolactin, growth hormone, adrenocorticotropin, thyrotropin, folitropin, or luteinizing hormone). Clinically non-functioning adenomas (CNFA) lacking the typical hypersecretion of hormones make up a significant portion of PA. The aim of the study was to determine the complete expression profiles of somatostatin receptors (SSTR1-SSTR5), dopamine receptors type 2 (D2R), and estrogen receptors (ER1) in various types of PA.

Methods: Adenoma specimens were obtained from 206 patients during transsphenoidal resection. For quantitative analysis, reverse transcription and consequent real-time PCR with synthetic multilocus calibrators (SMC) were used. The obtained data were normalized to the number of transcripts of the beta-glucuronidase gene.

Results: The use of SMC enabled the alignment of individual calibration functions for all the receptors. No relationships between the expression of the receptors and the tumor size, site of extension, gender or age at diagnosis were significant. In growth hormone-secreting adenomas, D2R and SSTR2 transcripts were extensively expressed, followed by ER1, SSTR5, SSTR3, and SSTR1. In patients with macroprolactinomas, transsphenoidal resection was indicated because dopamine agonists did not normalize prolactin levels. D2R, ER1 and SSTR1 transcripts were significantly transcribed. Corticotroph adenomas showed high levels of D2R and ER1 transcripts and lower amounts of SSTR2 and SSTR1 transcripts. SSTR5 transcripts were very low. Subjects with CNFA dominantly expressed D2R and ER1, followed by SSTR2 and SSTR3 mRNA.

Conclusion: We evaluated SSTR1-SSTR5, D2R, and ER1 expressions in a large group of pituitary adenomas and we found that determining their individual expression profiles could help when choosing the optimal postoperative treatment.

Keywords: pituitary adenoma, somatostatin receptor, dopamine receptor, estrogen receptor, real-time PCR, gene expression

Received: June 23, 2015; Accepted: November 11, 2015; Prepublished online: November 24, 2015; Published: June 24, 2016  Show citation