[Accumulation by preparations of rat heart sarcolemma of protein-bound forms of glucocorticoids].
The accumulation of free and protein-bound forms of [3H]corticosterone and [3H]dexamethasone by preparations of heart sarcolemma from adult male Wistar rats was studied. At physiological concentrations of glucocorticoids the sarcolemma preparations showed a considerably greater accumulation of the cytosol-bound form of glucocorticoids as compared to the free form. On the contrary, the formation of [3H]corticosterone-transcortine complex decreased the steroid uptake by the membranes under these conditions. The [3H]steroid-albumin complexes obtained by incubation of very high concentrations of [3H]glucocorticoids with pure albumin were retained by the membranes better than the free form of the hormones. The differences in the accumulation by membranes of steroid--cytosol and steroid--albumin complexes during temperature rise from 0 degrees to 20 degrees C were found. The increase in the uptake of steroid--cytosol complexes was evidently caused by thermal "activation" of the complexes, while the temperature influence on the steroid--albumin complexes accumulation by sarcolemma preparations was directly due to the uptake process. An addition of molybdate (blocker of steroid--receptor complexes activation) at a concentration of 100 mM completely eliminated the thermal effect on the steroid--cytosol complexes accumulation.
D000418:Albumins / Q000378:metabolism; D000818:Animals; D003345:Corticosterone / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D003907:Dexamethasone / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism*; D014316:Tritium
D000418:Albumins; D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D014316:Tritium; D003907:Dexamethasone; D003345:Corticosterone
Akkumuliatsiia preparatami sarkolemmy serdtsa krysy belkovosviazannykh form gliukokortikoidov.