[The mechanisms of the realization of the effect of glucocorticoids in aging]. / Mekhanizmy realizatsii éffekta gliukokortikoidov pri starenii.

The interaction of glycocorticoids with serum transport proteins, plasma membranes and rat liver cytoplasmic receptors progressively declines during ontogenesis, reaching its minimum at 24 months of age. Glycocorticoid receptor complexes (GRCs) binding to the rat liver nuclei and their residual fractions as well as the glycocorticoid-induced initiation of RNA-synthesis also decrease with age. The GRCs are shown to be capable of association with nuclear envelope, nuclear matrix and RNA-containing nuclear fraction isolated from the rat liver. The intracellular glycocorticoid receptor recycling requires fresh synthesis of the RNA and protein.

[The effect of nucleotides and molybdate ions on the activation of glucocorticoid-receptor complexes]. / Vliianie nukleotidov i ionov molibdata na aktivatsiiu gliukokortikoid-retseptornykh kompleksov.

The effects of various nucleotides and sodium molybdate on the activation of glucocorticoid-receptor complexes (GRC) isolated from tissue cytosol of 6- and 25-month-old rats was studied. It was shown that nucleoside triphosphates activate GRC in the livers of 6-month-old rats, the activating effect being decreased in the following order: UTP greater than or equal to ATP greater than GTP greater than or equal to CTP. Nucleoside di- and monophosphates exert a far lesser stimulating effect. These effects of nucleotides decrease with ageing. Molybdate ions exert a 3-fold effect on the activation of GRC from various rat tissues, i.e., stimulating, inhibiting and zero effects.

[Effect of irradiation on the intracellular reception of glucocorticoids in tissues with various radiosensitivities]. / Vliianie oblucheniia na vnutrikletochnuiu retseptsiiu glikokortikoidov v tkaniakh razlichnoi radiochuvstvitel'nosti.

The experiments with albino female rats showed that whole-body gamma-irradiation with a dose of 1 Gy caused various alterations in concentrations of cytoplasmic and nuclear glucocorticoid receptors depending on tissue radiosensitivity (liver, thymus) and postirradiation time-intervals (1, 3, 10, 30, and 60 days). There was also a change in the receptor affinity to glucocorticoids.

Steroid-receptor complexes and their interaction with the rat liver nuclei during ontogenesis.

Steroid-receptor complexes (SRCs) (glucocorticoids, estrogens and progestins) are isolated from rat liver and purified 1500-2000-fold. Both the initial cytosol complexes and those purified 2000-fold were characterized by gel filtration on Sephadex G-100 and DEAE-cellulose chromatography. The purified rat liver SRCs were used for binding to the isolated liver nuclei from rats of different ages (1.5, 6, 12, 24 months). Binding of progestin and estrogen-receptor complexes from rat liver to homological nuclei of 1.5-month-old rats is maximum, no distinct differences being found in the case of glucocorticoid-receptor complexes. SRC binding to the nuclei progressively declines with age, reaching its minimum by 24 months. The revealed differences in SRC binding by the nuclei of animals of different ages seem to be the basis of the hormone-induced changes in the organism functioning at various stages of ontogenesis.

[Estrogen- and progestin-receptor complexes and their interactions with rat liver cell nuclei in ontogenesis]. / Estrogen- i progestin-retseptornye kompleksy i ikh vzaimodeistvie s iadrami kletok pecheni krys v ontogeneze.

Steroid-receptor complexes (SRC) of estrogen and progestin were isolated from rat liver and purified 1500-2000-fold. The SRC within the composition of cytosol and purified 2000-fold were characterized by gel filtration of Sephadex G-100 and by DEAE-cellulose chromatography. The purified SRC from rat liver were bound to isolated liver cell nuclei of rats of various age (1.5, 6, 12 and 24 month-old). The maximal binding of progestin and estrogen SRC from rat liver was observed in homologous nuclei of 1.5-month-old animals. The binding of SRC by the nuclei decreased progressively with age, reaching its minimum in 24-month-old rats. The observed differences in the SRC binding by cell nuclei of experimental animals may be the cause of functional changes at various stages of ontogenesis.

[Age-related decrease of the binding of isolated rat liver and brain nuclei with glucocorticoid-receptor complexes]. / Vozrastnoe umen'shenie sviazyvaniia izolirovannymi iadrami pecheni i mozga krysy gliukokortikoid-retseptornykh kompleksov.

Isolated nuclei from liver and brain of rats of various age bind isolated and 1000-2000-fold purified glucocorticoid-receptor complexes (GRC) containing [3H]dexamethasone. The binding of GRC by the nuclei decreases with an increase in the NaCl concentration from 0 to 0.4 M in a medium. The maximal degree of GRC binding is observed in the liver and brain nuclei of newborn rats (1-day-old); the nuclei of adult animals aged 3 months bind GRC 1/2 times as much. in old (25-month-old) and grown-up animals, no significant differences in GRC binding by nuclei from respective tissues were revealed. Brain nuclei of newborn rats were shown to bind GRC to a greater extent than liver nuclei.

[Participation of chromatin proteins in the binding of glucocorticoid receptor complexes by the cell nucleus]. / Uchastie belkov khromatina v sviazyvanii gliukokortikoid-retseptornykh kompleksov kletochnym iadrom.

The binding of the purified glucocorticoid-receptor complexes from rat liver cytosol with partially deproteinized and partially reconstituted chromatins from rats liver and brain has been investigated. The chromatin was deproteinized by stepwise extraction of nuclei with NaC1 solution of raised molarity. The partial chromatin reconstruction was accomplished by the addition of individual fractions of extracted proteins to DNA-cellulose. It has been shown that in both test-systems used some fractions of nuclear proteins in particular the fractions of loosely associated with chromatin nonhistone proteins are capable of modulating specifically (mainly positively) the binding of glucocorticoid-receptor complexes with chromatin.

[Comparative analysis of the interaction of highly purified glucocorticoid-receptor complexes from rat liver with homologous and heterologous cell nuclei]. / Sravnitel'nyi analiz vzaimodeistviia vysokoochishchennykh gliukokortikoid-retseptornykh kompleksov pecheni krys s gomologichnymi i geterologichnymi kletochnymi iadrami.

The binding of glucocorticoid-receptor complexes (GRC) from rat liver purified 1000-2000-fold to homologous and heterologous cell nuclei was investigated. The purified GRC preparations were examined by gel filtration, ion-exchange chromatography on DEAE-cellulose and electrophoresis in polyacrylamide gel in the presence of Na-DS. The binding of GRC to the nuclei was characterized in terms of associate resistance to KCl. It was found that the isolated nuclei of the non-homologous tissue of the same species (rat brain) or of the heterologous tissues (liver and brain) of phylogenetically different species (pigeon, frog) can bind rat liver GRC in the same degree or even more than the homologous nuclei. Some tissue- and species-dependent peculiarities of GRC binding capacity of the nuclei were revealed. The GRC binding capacity of pigeon nuclei is somewhat higher than that of rat nuclei, while the corresponding ability of frog brain nuclei is higher than that of frog liver nuclei. The GRC-nuclei associates are more resistant to KCl than the GRC--pure DNA associates.