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Biomedical subjects

A G Volchek

Publications and source records attributed to A G Volchek.

At least 19 recordsLinked to original sources
PubMed1976

[Protein binding glucocorticoid hormones (transcortin) during peri-and postnatal ontogenesis and pregnancy in rats].

The constants of association and the energy of interaction between transcortin and cortisol, the binding ability and other characteristics of transcortin have been studied in the embryos, sexually immature and mature young and old females, females on the 14th and 21st days of pregnancy, immature and mature males. The constant of association in all the groups amounted to ca. 10(8) and the energy of interaction ca. 10 Cal/mole. The embryos and immature rats of both sexes are characterized by relatively low levels of the binding ability of transcortin. During the sexual maturation, the level of transcortin increased--insignificantly in males and markedly in females. The level of transcortin in the latter remained almost invariable during pregnancy and senescence. By the electrophoretic and sedimentation properties transcortin was the same in different groups. The high level of transcortin during pregnancy corresponded to the high level of hormones bound by transcortin, the level of these hormones in the embryos being much lower than in the mother.

Age Factors↗
PubMed1976

[Comparative characteristics of cytosol glucocorticoid receptors from normal liver, the liver of tumor-bearing rats and hormone unresponsive Zajdela hepatoma].

Specific dexametasone (D) and cortisol (F) receptors have been found both in liver and Zajdela hepatoma. Rat liver cytosol receptors are characterized by the association constant (Kas) = 3,8 X 10(8) M-1 for D and 0,57 X 10(8) M-1 for F as well as by a number of binding sites (NBS)=4,9 X 10(-13) moles/mg protein and 4,06 X 10(-13) moles/mg protein, respectively. The receptors show stric specificity to glucocorticoids. Cytosol glucocorticoid-receptor complexes from liver and hepatoma sediment at 6-7S, when centrifuged in the buffer of a low ionic strength, and at 3-4S in the buffer of a high ionic strength (0,4 M KCl). The properties of cytosol receptors in the course of in vivo hepatoma growth were found to be gradually altering: Kas for D dropped whereas that for F increased; the NBS is decreased 3-4 fold as compared to normal liver cytosol--which may partially be accounted for by the unresponsiveness of the tumour to the hormones.

Animals↗
PubMedDate not supplied

[Study of the characteristics of transcortin and the progesterone binding protein of the plasma of pregnant guinea pig].

Experiments were conducted with the plasma of pregnant guinea pigs; it was shown that the corticosteroid-binding protein (CBP) of the plasma in a pregnant guinea pig (in difference from the CBP of other species) bound cortisol only, and not progesterone. Progesterone-binding protein (PBP) of these animals bound progesterone, but not glucocorticoids and their metabolites. The binding capacity of CBP proved to be several hundred microgram per cent of cortizol and of PBP--about 100 microgram per cent of progesterone. The association constant of the CBP with cortisol constituted 10(6) M-1, and of the PBP-10(-8) M-1. These proteins are also analysed according to a number of other parameters.

Animals↗