[Independence of the insulin effect from the guanosine-3',5'-monophosphate level in muscle tissue]. / Nezavisimost' éffekta insulina v myshechnoi tkani ot urovnia guanozin-3',5'-monofosfata.

The role of cyclic GMP in the insulin effect was investigated using isolated frog sartorii. A study was made of the effect of exogenous cyclic GMP, dibutyryl cyclic GMP, 8-bromo-cyclic GMP on xylose transport, glycogen synthesis and muscle respiration. Only dibutyryl cyclic GMP (1.10(-6) - 10(-4) M) alone was observed to have a stimulating effect on glycogen synthesis and respiration. The xylose transport was but slightly accelerated only following a 20 hours incubation of muscles in the cyclic GMP solution. Cyclic GMP was shown to penetrate the muscle fibres. The cyclic GMP content in muscles was equal to 22.7 +/- 2.0 pM per gram of wet weight. Insulin exerted no effect on cyclic GMP concentration in muscles. The data obtained do not allow to conclude that cyclic GMP may serve as a mediator in realization of the insulin effect on membrane and intracellular processes.

[Cellular energy functions of a subline of mouse fibroblasts resistent to the action of ethidium bromide]. / Izuchenie nekotorykh énergeticheskikh funktsii kletok sublinii myshinykh fibroblastov, rezistentnoi k deistviiu bromistogo étidiia.

The respiration of subline Leb-25 cells, resistant to ethidium bromide (EB, 25 g/ml), is 2.5 times slower than the respiration of parental L cells of mouse fibroblasts. The EB resistant cells have a normal level of ATP. Disturbances of mitochondrial functions can be observed such as a defect of the succinate dehydrogenase complex and the uncoupling of respiration and oxidative phosphorylation in mitochondria of Leb-25 cells.

[Effect of cyclic nucleotides and histone fractions on mitochondrial respiratory and phosphorylating activity]. / Vliianie tsiklicheskikh nukleotidiv o nekotorykh fraktsii gistonov na dykhatel'nuiu i fosforiliruiushchuiu aktivnost'.

CAMP in the wide range of concentrations (3.10(-7)--10(-3) M), cGMP (10(-6)--10(-5) M) and dibutyril-cAMP (3.10(-6) M) produced no effect on oxidative phosphorylation of rat liver mitochondria. Among histone fractions (H1, H3 and H4) tested, the arginine-rich fraction H3 (18 microgram/mg of mitochondrial protein) produced a strong uncoupling effect. It is supposed that the effect of cAMP on oxidative phosphorylation of mitochondria may be carried out indirectly through activation of protein kinase, phosphorylation of histones, and their release into the cytoplasm.

[Effect of insulin and adrenaline on the respiration and glycolysis of the skeletal muscle of frog]. / Vliianie insulina i adrenalina na dykhanie i glikoliz skeletnykh myshts liagushki.

It was shown in the experiments on isolated sartorius muscles of the frog that insulin increased endogenous respiration by 10 mm3 O2 hr per gramm of wet weight. The effect of insulin and epinephrine on respiration is additive. Insulin in middle (5--50 milliunits/ml) and low, physiological, (50 microunits/ml) concentration does not induce acceleration of glycolyses. The conclusion was confirmed that the increase of the endogenous respiration by insulin cannot be accounted for by the mobilization of the substrate of glycolysis. In the presence of epinephrine, the low concentration (50 microunits/ml) of insulin induces the decrease of the content of glucose-6-phosphate. It is probably connected with the influence of insulin on the concentration level of the cAMP.

[Effect of insulin of frog skeletal muscle respiration]. / Vliianie insulina na dykhanie skeletonoi myshtsy liagushki

The respiration of the isolated frog sartorius muscle was measured polarographically. The endogenous respiration was seen to increase by 8 and 6 times in 20 mM KCL and 0.05 mM 2,4-DNP, resp., and by 40 percent in 10mM pyruvate or lactate. Insulin stimulated the endogemous respiration from 27 to 38 mm-3 O2/hr. per gramm of wet weight. In the excess of exogenous lactate and pyruvate, the degree of the insulin stimulated respiration did not change. It is suggested that the increase of the endogenous respiration by insulin cannot be accounted for by the mobilization of the substrate of glycolysis.