[Effects of hydrocortisone and insulin on the electrokinetic potential of hepatocyte nuclei]. / Elektrokineticheskii potentsial iader gepatotsitov pri vozdeistvii gidrokortizona i insulina.

The electrokinetic potential of liver cell nuclei of rats after the in vivo separate and joint injection of hydrocortisone and insulin was determined. It was shown that the steroid induces a significant elevation of the value of electrokinetic potential while insulin does not change this parameter. An insignificant elevation of the potential by the joint action of the hormones was found, which apparently is indicative of the antagonism between hydrocortisone and insulin.

[Change in electrokinetic potential in rat brain synaptosomes exposed to estradiol]. / Izmenenie élektrokineticheskogo potentsiala sinaptosom mozga krys pri vozdeistvii éstradiola.

The effect of different estradiol concentrations on electrokinetic potential of rat brain synaptosomes has been investigated. Changes in synaptosome electrokinetic potential at early stages of estradiol action are shown. The data obtained show that synaptosomes may be used as a model system to study the correlation between electrokinetic potential of cells and their physiological and biochemical status.

[Composition of labile-bound non-histone chromatin proteins in the rooster liver after treatment with estradiol]. / Izuchenie sostava labil'no sviazannykh negistonovykh belkov khromatina pecheni petushkov pri vozdeistvii éstradiola.

Preparations of chromatin and labile-bound nonhistone proteins were isolated from cockerel liver cells after treatment of birds with estradiol as well as from controls. Six protein fractions were obtained by means of column chromatography on DEAE cellulose: two of these fractions were quantitatively altered due to the hormonal effect. Electrophoretic separation of both total labile-bound nonhistone proteins and their hormone-dependent fractions showed that protein composition was altered after the estradiol treatment as compared with controls.

[Study of the changes in rat liver chromatin after hydrocortisone administration]. / Issledovanie izmenenii v khromatine pecheni krys pri vozdeistvii gidrokortizona.

After hydrocortisone administration some properties of rat liver chromatin were studied by means of melting technique and circular dichroism. Hydrocortisone caused a more than 2.5-fold increase in amount of the chromatin active fraction. Distinct differences were detected between circular dichroism spectra of total chromatin and of its active fraction as well as between differential curves of the chromatin active fraction melting in control and test samples. The difference was expressed as a decrease in temperature of melting in a low-point zone and as appearance of the secondary maxima in the region of nucleosomes melting. These data suggest that the decondensation of nucleosome-containing sites takes place which is considered as an indirect evidence of the chromatin activation.

[Polypeptide synthetase activity of chromatin from eukaryotic cells]. / Polipeptidsintetaznaia aktivnosy' khromatina kletok eukariotov.

It is shown that the polypeptide synthetase activity (PS-activity) of chromatin from rat liver is increased 9--21 hrs after partial hepatectomy. Among 9 amino acids studied alanine, methionine, lysine, tyrosine and arginine are not incorporated into the system in question. The highest rate of polymerization is observed in case of glutamic acid. The rate of glutamine, asparagine and glycine incorporation is 7--8 times slower. The PS-activity of chromatin is enhanced by chromatin preincubation with NAD (but not with its analogs). The activation is prevented by thymidine and nicotinamide. Storage of chromatin for 18 hrs at 2--4 degrees C results in a complete loss of PS-activity. Ability of "old" chromatin to incorporate of amino acids may be restored by its preincubation with NAD. Storage of chromatin in the presence of 5 mM cAMP does not decrease the PS-activity. It is assumed that in the system described poly-ADP ribose is an energy source for amino acid activation.