Endocrine Abstracts

Introduction: In addition to its well known effects on calcium homeostasis and bone metabolism, growing evidences shows that vitamin D plays an important role in regulation of cancer angiogenesis, cell apoptosis, differentiation, and proliferation. Vitamin D acts through vitamin D receptor (VDR), an intracellular nuclear receptor. It was found an association between different cancer histotypes and single nucleotide polymorphisms (SNPs) of VDR. Despite the close relationship between VDR and PIT-1 (pituitary trascription factor) suggests a potential role of vitamin D pathway in the onset of pituitary adenomas, however, to date no data are available on this issue.

Aim: This study evaluated 25OHvitD serum levels and VDR-SNPs expression in patients with non-functioning pituitary adenomas.

Patients and methods: We evaluated 14 patients with non-functioning pituitary adenomas and 14 healthy controls age and sex matched. Serum 25OHvitD levels were measured by solid-phase chemiluminescent enzyme immunoassays. The SNPs-VDR evaluated included Fok -1 and Taq-1, whose assessment was performed by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis.

Results: Serum 25OHvitD levels were significantly lower in patients (17.4±2.4 ng/ml) than in controls (31.3±1.7 ng/ml) (P<0.01). Allelic variants of Taq-1 VDR polymorphism had a different distribution in patients than in controls, with the variant TT and Tt present in 66 and 30% of patients and in 50 and 47% of controls (P=NS), respectively. Allelic variants of Fok-1 VDR polymorphism were distributed similarly in patients and in controls.

Conclusions: Serum 25OHvitD levels are significantly lower in patients with non-functioning pituitary adenomas than in controls, suggesting a potential etiopathogenetic and therapeutic role of vitamin D pathway in these patients. The significance of different distribution of allelic variants of Taq-1 VDR polymorphism between patients and controls requires further investigation.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.