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Biomedical subjects

L E Panin

Publications and source records attributed to L E Panin.

At least 91 records · Page 5Linked to original sources
PubMed1979

[Change in the activity of the key gluconeogenesis enzymes in the rat liver and kidneys during the action of subextreme and extreme factors on the body].

The activity of glucogenesis key enzymes (phosphoenolpyruvate carboxinase, fructoso-1,6-siphosphatase, glucoso-6-phosphatase) of the rat liver and kidneys was studied simultaneously under the effect of extreme and subextreme factors on the organism. The low initial phosphoenolpyruvate carboxikinase activity in the liver and its high inductivity under extreme conditions suggest a role of this enzyme as limiting link in glyconeogenesis. The activity of phosphoenolpyruvate carboxinase in the kidneys is comparable to that of fructoso-1,6-diphosphatase; it is considerably higher than the activity of glucoso-6-phosphatase. The phosphoenolpyruvate carboxinase activity in the kidneys is 5--6 times higher than in the liver. The activity of phosphoenolpyruvate carboxinase and glucoso-6-phosphatase is increased under the effect of extreme factors, and that of fructoso-1,6-diphosphatase remains unchanged. The lack of clear synchronous changes in the activity of glucogenesis key enzymes in the liver and kidneys indicates that the cells of these organs do not provide the united operon for phosphoenolpyruvate carboxinase, fructoso-1,6-diphosphatase and glucoso-6-phosphatase with common regulation mechanism.

Adaptation, Physiological↗
PubMed1979

[Mechanism of regulation of steroidogenesis in the adrenals by blood serum lipoproteins].

It has been shown that high density lipoproteins obtained by ultracentrifugation and loaded with cholesterol and pregnenolone exert a stimulant effect on in vitro production of glucocorticoids by rat adrenals. Low density native lipoproteins possess an inhibitory effect connected with the protein component. The action of various blood serum lipoproteins on steroidogenesis in rat adrenals has significantly different mechanisms.

Adrenal Glands↗
PubMed1978

[Effect of adrenaline, hydrocortisone, insulin and dibutyryl-cAMP on glycolysis and glycogenolysis in white rat liver slices].

Epinephrine, hydrocortisone, and dibutyril cAMP inhibited glycolysis and glucogenolysis. The inhibitory effect was also found when glucose-6-phosphate (G-6-P) was used as a glycolysis substrate, but not for fructose-1,6-diphosphate. This is the evidence of hexokinase activity inhibition by hormones and dibutyril cAMP, and presumably of phospholylase and phosphofructokinase as well. In the simulated cell-free system the hormones produced no effect, dibutyril cAMP inhibiting hexokinase alone. For the realization of hormones effect their interaction with the cell membrane is required. Inhibition of glycogen and G-6-P decomposition to lactic acid in the rat liver slices was not associated with the hormone action on phosphorylase and phosphofructokinase through cAMP and proteinkinase directly. The results obtained indicated the existence of a supplementary mechanism that modified cAMP effect on the activity of the said enzymes. Insulin was effective in any of the cases.

Animals↗
PubMed1978

[Change in the state of the lysosomes in isolated Kupffer cells and hepatocytes in the process of liver reparative regeneration].

Using hepatectomized rats, it was shown that immediately after a partial liver removal the Kupffer macrophages were accumulated. At the maximal mitotic activity (36 hours following partial hepatectomy), the relative amount of Kupffer cells keeps low, but 72 hours later turns out to be higher again. The periodic changes of the Kupffer cell amount in hepatectomized rats are accompanied by remarkable increase (by 1.5--3 times) of free and total lysosomal enzymes (acid DNAase, DNAase, cathepsin D). The activation of the Kupffer macrophage lysosomes goes ahead of labilization of hepatocyte lysosomal membranes. The blockade of mononuclear phagocyte system by means of carbonate iron in an early prereplicative period leads to an as long as 10--12 hours retardation of hepatocyte proliferation. The role of the Kupffer macrophages in reparative liver regeneration is discussed.

Animals↗
PubMed1977

[Effect of sub-extreme and extreme factors on liver lysosomes].

Functional state of the lysosomal liver system in rats under subextreme and extreme influences (an intense muscle tension, fasting and combination of the both factors) was studied. An elevation of the acid hydrolases activity and labilization of the lysosomal membranes could be observed in the course of the body overstraining. Activation of lysosomal system correlated well with the extent of overstraining and reflected an adaptive reconstruction of the cellular structure and metabolism.

Animals↗
PubMed1976

[Study of the relationship between the glucocorticoid function of the adrenal cortex and blood lipoproteins].

Single administration of hydrocortisone to rats led to elevation in the blood serum of lipoproteins of very low density; and repeated administration - of lipoproteins of very low density, low density and of high density. Lipoproteins with d less than 1.063 g/ml produced an inhibitory action on the production of steroid hormones by the adrenal glands of rats in vitro.

11-Hydroxycorticosteroids↗
PubMedDate not supplied

Binding and transport of benzo[a]pyrene by blood plasma lipoproteins: the possible role of apolipoprotein B in this process.

The role of plasma lipoproteins as carriers in the transport of benzo[a]pyrene was assessed in in vitro and in vivo studies. Addition of [3H]benzo[a]pyrene to rat plasma resulted in binding of the xenobiotic to lipoproteins. Studies of labeled benzo[a]pyrene distribution in rat blood plasma by the method of ultracentrifugation have given the following results: high-density lipoproteins, 40%; low-density lipoproteins, 14%; very-low-density lipoproteins, 23%; other plasma proteins, 23%. Complexes of benzo[a]pyrene-lipoproteins were isolated by gel filtration with Sephadex G-25 and used for intravenous injection in rats. Biodistribution studies have shown different localization of benzo[a]pyrene in rat organs and tissues depending on lipoprotein classes. A high amount or radioactivity was bound by the liver and adrenals when all classes of lipoproteins were used, but especially with high-density lipoproteins. High levels of benzo[a]pyrene were measured in the kidneys. Equilibrium dissociation constants for complexes of benzo[a]pyrene with high-density lipoproteins and low-density lipoproteins were obtained (Kd 4.1 x 10(-5) and 1.5 x 10(-5) M, respectively). Binding and distribution of the protein component of lipoproteins were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. More than 80% of the radioactivity recovered from the gel was localized in the area of apolipoprotein B. After isolation and purification of apolipoprotein B, the equilibrium dissociation constant for complexes of benzo[a]pyrene with apolipoprotein B was obtained, and its value indicated that apolipoprotein B might be the main protein carrier for benzo[a]pyrene.

Animals↗
PubMedDate not supplied

[Effect of tetrahydrocortisol-apolipoprotein A-I complex on RNA polymerase interaction with eukaryotic DNA and the rate of protein biosynthesis in hepatocytes].

A mechanism of activation of protein biosynthesis in hepatocytes was proposed as effected by the conditioned medium of nonparenchymal liver cells incubated in the presence of high density lypoproteins, cortisol, and lypopolysaccharides. It was found that the increase in the biosynthesis rate was associated with the formation of the tetrahydrocortisol-apolipoprotein A-I (THC-apoA-I) complex in macrophages, which display 5 alpha- and 5 beta-reductase activity and are constituents of nonparenchymal liver hepatocytes. Using the small-angle X-ray scattering technique, it was shown that the THC-apoA-I-eukaryotic DNA interaction may break hydrogen bonds between pairs of complementary nucleic bases and cause the formation of single-stranded DNA fragments capable of binding to DNA-dependent RNA polymerase. The interaction is highly cooperative and has a saturating mode, up to six enzyme molecules being bound per DNA molecule.

Animals↗
PubMedDate not supplied

Enzyme-linked immunosorbent assay for apolipoproteins A-I and B in the urine of patients with nephrotic syndrome.

Enzyme-linked immunosorbent assay (ELISA) has been used for measuring apolipoproteins A-I and B in the urine. ApoB is absent in urine of healthy subjects, and apoA-I is determined in trace quantity. In patients with chronic glomerulonephritis quantity of apoA-I in urine was 117 times as much as in control group. ApoB is present in urine of patients in considerable quantity (1528 +/- 315 micrograms/l). The ELISA method for determining apoA-I and apoB in urine makes it possible to evaluate the gravity of pathological process in kidney.

Adult↗