Benzene and 2-ethyl-phthalate induce proliferation in normal rat pituitary cells.

Purpose: Endocrine disruptors are known to modulate a variety of endocrine functions and increase the risk for neoplasia. Epidemiological data reported increased prevalence of pituitary tumors in high industrial areas while genotyping studies showed that mutations in the aryl hydrocarbon receptor (AhR) interacting protein (AIP)-chaperone to the dioxin ligand AhR-gene are linked to predisposition to pituitary tumor development. Aim of the present study was to establish whether endocrine pollutants can induce cell proliferation in normal rat pituitary cells.

Methods: Pituitary primary cultures were incubated with 250, 650 and 1250 pM benzene or 2-ethyl-phthalate for up to 96 h and viability, energy content and cell proliferation assessed. Expression of pituitary tumor transforming gene (PTTG), cyclin D1 (Ccnd1), AhR and AIP was quantified by RT-qPCR.

Results: Incubation with benzene or 2-ethyl-phthalate increased viability and energy content in pituitary cells. The endocrine disruptors also increased cell proliferation as well as Ccnd1 and PTTG expression. Increased AhR and AIP expression was observed after incubation with the two pollutants.

Conclusions: Our findings indicate that benzene and 2-ethyl-phthalate activate AhR/AIP expression and stimulate proliferation in normal rat pituitary cells. This study is the first demonstration that pollutants can induce normal pituitary cells to proliferate and provides a link between epidemiological and genomic findings in pituitary tumors.