Dopamine regulates D2 receptor gene expression in normal but not in tumorous rat pituitary cells.

Abnormalities of dopamine D2 receptors may be implicated in the development of some pituitary tumours. Previously we have identified dopamine D2 receptor gene expression both in normal rat pituitaries and in dopamine resistant GH3 rat pituitary tumour cells. In this study we have examined the effect of dopamine on D2 receptor gene expression in these cells using a probe specific for both D2 receptor isoforms. Normal rat pituitary cells were maximally stimulated by 100 nM dopamine at which concentration D2 receptor mRNA concentrations were 400% greater than that measured in controls. No increase in D2 receptor gene expression was observed in GH3 pituitary tumour cells.