Steroid hormone specifically binds to rat kidney plasma membrane.

A high-affinity and low-capacity corticosterone specific binding was detected in the purified plasma membrane preparation from rat kidney using an in vitro steroid hormone binding assay. The specific-bound hormone was efficiently distinguished from the irreversible-bound hormone with 10 microM corticosterone. Under standardized conditions of pH 7.4 at 2 degrees C and 30 min incubation time, the binding was saturable and showed Kd = 13 +/- 3 nM and Bmax = 616 +/- 34 fmol/mg of protein. Competitive binding studies with analogue steroids indicated that corticosterone binding to kidney plasma membrane is hormone-specific. Results indicated that the possible nongenomic effects of steroids could be mediated by their interaction with plasma membrane.