[Interaction of transcortin and type III glucocorticoid receptors with type II glucocorticoid receptors in stress].

Amount of corticosterone-binding sites in transcortin from blood plasma of intact rats constituted 2960 fmole/mg of protein, in the animals with stress reaction caused by immobilization within 24 hrs--1630 fmole/mg. Dissociation constants of the complex corticosterone-transcortin were 4.6 nM and 9.3 nM, respectively. In liver cytosol of intact animals content of glucocorticoid receptors of the III type was 240 fmole/mg, in the animals with stress reaction--66 fmole/mg; dissociation constants of the complex corticosterone-glucocorticoid receptors of the III type were 6.1 nM and 6.3 nM, respectively. Amount of glucocorticoid receptors of the II type was 310 fmole/mg in liver cytosole of intact rats and in the animals with stress--250 fmole/mg; dissociation constants of the complex transcortin-glucocorticoid receptors of the II were 10.6 nM and 20.8 nM, respectively. A decrease in transcortin content led to an increase in the level of free glucocorticoids in blood with simultaneous elevation in the positive gradient of free glucocorticoid concentration and in the rate of steroid diffusion in to cells. At the same time, after a decrease in the tyre III glucocorticoid receptors the formation of complexes of glucocorticoid receptors of the II type-steroids was accelerated and translocation of the complex into cell nuclei was stimulated. Proteolytic enzymes appear to be responsible for transformation of glucocorticoid receptors of the III tyre into the receptors of the II type.