Nonylphenol, an environmental estrogen, affects voltage-gated K⁺ currents and L-type Ca²⁺ currents in a non-monotonic manner in GH₃ pituitary cells.

We have investigated the characteristics of voltage-gated K(+) channels and L-type Ca(2+) channels in GH3 rat pituitary cells and the effects of the xenoestrogen (XEs) nonylphenol (NP) on these ion channel currents. Our results have shown that the lower concentrations (10(-15)-10(-14)M) of NP decreased the amplitudes of voltage-gated K(+) currents (IKv) and activated L-type Ca(2+) currents (ICa-L) by reducing half-activation membrane potentials of activation kinetics curves. However, the higher concentrations (10(-10)-10(-9)M) of NP increased the amplitudes of IKv and inhibited ICa-L by reducing the peak values of ICa-L. Thus, NP affects IKv and ICa-L in an opposite and non-monotonic manner.