[The effect of iodine-131 on the binding characteristics of sex and thyroid hormones by blood plasma proteins in children with a functional thyroid disorder as a result of the accident at the Chernobyl Atomic Electric Power Station]. / Vliianie ioda-131 na kharakteristiki sviazyvaniia polovykh i tireoidnykh gormonov belkami plazmy krovi u detei s funktsional'nym narusheniem shchitovidnoi zhelezy v rezul'tate avarii na ChAES.

In studying characteristics of specific interaction of estradiol-, testosterone- and thyroid-binding blood globulins with the corresponding ligands in children from Gomel Province with endemic swelling of the thyroid gland (degrees I and II) affected by iodine-131 revealed were a reduced cooperativity in estradiol and T-3 binding and a halved affinity to androgens and thyroids as compared to healthy controls. In addition, there was a drastic decline in the binding capacity of estradiol- and testosterone-binding globulins in the blood plasma. The endemic thyroid gland swelling is supposed to be due to sexual malfunction in teenagers.

[Interaction of [3H] corticosterone from blood serum with rat liver cells during aging]. / Vzaimodeistvie [3H] kortikosterona syvorotki krovi s kletkami pecheni krys pri starenii.

It is shown that the consumption of glucocorticoids from the complexes with serum proteins by hepatocytes decreases with ageing. Transcortin-complexed decrease adenosine monophosphate binding by the liver cells but the degree of this inhibition decreases with an increase of animals' age, which is probably connected with the change in physicochemical properties of steroid-transport blood glycoprotein.

[Interaction of [3H]AMP with liver cells and their plasma membranes]. / Vzaimodeistvie [3H]AMP s kletkami pecheni i ikh plazmaticheskimi membranami.

Specific binding of [3H]AMP to rat hepatocytes and their plasma membranes was studied. It was shown that the time course of this binding reached a maximum within the first 15 seconds. An equilibrium binding study revealed the presence of a single class of binding sites with Kd of 20 microM both in hepatocytes and in plasma membranes. The [3H]AMP binding sites were inactivated by treatment with trypsin as well as by heating. 5'-Phosphorylated derivatives of adenosine (ATP, ADP) effectively competed with [3H]AMP for the binding sites, while adenosine, beta-glycerophosphate and 3'-AMP were inactive. The binding of [3H]AMP increased by 400% in the presence of concanavalin A, a specific inhibitor of plasma membrane 5'-nucleotidase. It was concluded that the catalytic center of 5'-nucleotidase is a receptor for adenine nucleotides.

[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.

[Association of [3H]-dexamethasone with cytoplasmic receptor proteins and their translocation into liver cell nuclei during aging]. / Assotsiatsiia [3H]-deksametazona tsitoplazmaticheskimi retseptornymi belkami i ikh translokatsiia v iadra kletok pecheni pri starenii.

Interaction of 3H-dexamethasone with cytoplasmic proteins was studied in male rat liver cells. With ageing of the animals concentration of high affinity and low affinity glucocorticoid receptors was decreased 2-fold as well as the corresponding reduction of nuclear uptake in the steroid-receptor complexes was found. A protein species was found in cytoplasm of aged rat hepatocytes, which bound 3H-dexamethasone with "extremely low" affinity and was not able to associate with the cell nuclei.

[Age-related characteristics of corticosteroid interactions with blood transport proteins]. / Vozrastnye osobennosti vzaimodeistviia kortikosteroidov s transportnymi belkami krovi.

In blood of old rats the content of corticosteroid transport proteins was decreased, as a result of which their balance was distorted and negative cooperativity between transcortin-binding sites developed. Values of Hill coefficient were below 1 in the hormone-protein interactions, which appears to occur due to polymerization of the protein or to appearance of unknown factors(s) in blood of old animals. After treatment of the old rats blood serum with activated charcoal the steroid-binding transcortin capacity and its affinity to hormone was increased and the negative cooperativity was not observed.