Interaction of cortisol with the neural retina of the chick embryo in culture.

The uptake of cortisol and the kinetics of hormone-receptor interaction in the cytosol and cell nucleus were investigated in the intact tissue in organ culture. Cortisol is concentrated by the neural retina. The accumulation of the free steroid is temperature dependent but the effect of temperature decreases with the increase of cortisol in medium. Cortisol binding to specific receptors in the cytosol shows a sigmoidal type of kinetics which correlates well with the kinetics of glutamine-synthetase induction by cortisol. The temperature dependent translocation of the receptor-hormone complexes to the nuclei and the effect of detergents on the binding to nuclei are presented.