RERG is a molecular correlate of the inward-rectifying K current in clonal rat pituitary cells

The rat homologue of the human ether-g-go-go-related gene (r-erg) was cloned from rat brain using homology screening. RERG has a 96% amino acid identity to HERG. Membrane currents recorded in CHO cells after previous injection of r-erg showed that the voltage- and time-dependent properties are indistinguishable from h-erg-induced currents expressed in the same system. RT-PCR revealed the presence of r-erg mRNA in clonal rat pituitary cells (GH(3)/B-6 cells). These cells exhibit a voltage-dependent inward-rectifying K current (I-K,I-IR) which is highly sensitive to the class III antiarrhythmic E-4031. I-K,I-IR recorded in GH(3)/B-6 cells and ERG currents in CHO cells were compared using similar experimental conditions (same pulse protocols and isotonic KCI as extracellular solution). The voltage- and time-dependent properties of both currents were found to be almost identical. These results strongly suggest that RERG channels mediate I-K,I-IR in GH(3)/B-6 cells.