Stimulating Influence of a Flavonolignane Derivative on Proliferation, RNA Synthesis and Protein Synthesis in Liver Cells

1987 ◽  
pp. 265-272 ◽  
Author(s):  
J. Sonnenbichler ◽  
I. Zetl
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Liver Cells

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

The Effect of Insulin on the Growth and Metabolism of the Human Diploid Cell, Wi-38

1970 ◽  
Vol 7 (2) ◽  
pp. 575-585
Author(s):  
J. B. GRIFFITHS
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Glucose Uptake ◽  
Rna Synthesis ◽  
Cultured Cells ◽  
Cell Sheet ◽  
High Energy ◽  
Contact Inhibition ◽  
Contributory Factor ◽  
Membrane Area

In a confluent culture of WI-38 cells the membrane area available for nutrient uptake is greatly reduced and the possibility exists that this reduction in uptake capacity of the cell is a contributory factor in contact inhibition. Insulin has been reported by many authors to facilitate glucose uptake and also to stimulate protein, DNA and RNA synthesis, glycolysis, pino-cytosis and growth in cultured cells. The effect of insulin on WI-38 cells was determined, therefore, to find out whether it enabled the cell to escape from contact inhibition of growth. The action of insulin was found to be dependent upon medium composition. Growth and protein synthesis were stimulated in Eagle's minimal essential medium, but not when this medium was supplemented with glucose and glutamine. Apparently insulin is only effective when high-energy compounds become limiting. Whilst insulin did not induce any post-confluent division, the protein content of cells was increased by 30%, and this was correlated with an increased rate of protein synthesis. Despite this increased activity in protein metabolism, the utilization of amino acids was less in the presence of insulin indicating that a control mechanism for more economical utilization of amino acids for protein synthesis was activated by insulin. Insulin had no effect on RNA synthesis, and only a slight inhibitory effect on DNA synthesis. Evidence was produced suggesting that insulin blocked cell division and encouraged differentiation. Glucose uptake and incorporation into the cell was stimulated by insulin, and this was especially noticeable after the cell sheet became confluent. The turnover of labelled glucose and derivatives was also enhanced by insulin and this was accompanied by a much higher rate of lactic acid production. It is concluded that insulin does not overcome contact inhibition and permit post-confluent division, but that it does enable the cell to take up and utilize nutrients more efficiently in confluent cultures with a resultant increase in metabolic activity and cell size.

Stabilization of tubulin mRNA by inhibition of protein synthesis in sea urchin embryos

1988 ◽  
Vol 8 (8) ◽  
pp. 3518-3525
Author(s):  
Z Y Gong ◽  
B P Brandhorst
Keyword(s):  
Protein Synthesis ◽  
Sea Urchin ◽  
Mrna Stability ◽  
Rna Synthesis ◽  
Rapid Loss ◽  
Transcription Analysis ◽  
Inhibition Of Protein Synthesis ◽  
Tubulin Mrna ◽  
Autogenous Regulation

An increased level of unpolymerized tubulin caused by depolymerization of microtubules in sea urchin larvae resulted in a rapid loss of tubulin mRNA, which was prevented by nearly complete inhibition of protein synthesis. Results of an RNA run-on assay indicated that inhibition of protein synthesis does not alter tubulin gene transcription. Analysis of the decay of tubulin mRNA in embryos in which RNA synthesis was inhibited by actinomycin D indicated that inhibition of protein synthesis prevents the destabilization of tubulin mRNA. The effect was similar whether mRNA was maintained on polysomes in the presence of emetine or anisomycin or displaced from the polysomes in the presence of puromycin or pactamycin; thus, the stabilization of tubulin mRNA is not dependent on the state of the polysomes after inhibition of protein synthesis. Even after tubulin mRNA declined to a low level after depolymerization of microtubules, it could be rescued by treatment of embryos with inhibitors of protein synthesis. Tubulin mRNA could be induced to accumulate prematurely in gastrulae but not in plutei if protein synthesis was inhibited, an observation that is indicative of the importance of the autogenous regulation of tubulin mRNA stability during embryogenesis. Possible explanations for the role of protein synthesis in the control of mRNA stability are discussed.

Conditions necessary for inhibition of protein synthesis and production of cytopathic effect in Aedes albopictus cells infected with vesicular stomatitis virus

1982 ◽  
Vol 2 (1) ◽  
pp. 66-75
Author(s):  
S Gillies ◽  
V Stollar
Keyword(s):  
Protein Synthesis ◽  
Vesicular Stomatitis Virus ◽  
Aedes Albopictus ◽  
Rna Synthesis ◽  
Cytopathic Effect ◽  
Viral Gene ◽  
Inhibition Of Protein Synthesis ◽  
Infected Cells ◽  
Vesicular Stomatitis ◽  
Aedes Albopictus Cells

The relationship between the development of cytopathic effect (CPE) and the inhibition of host macromolecular synthesis was examined in a CPE-susceptible cloned line of Aedes albopictus cells after infection with vesicular stomatitis virus. To induce rapid and maximal CPE, two conditions were required: (i) presence of serum in the medium and (ii) incubation at 34 degrees C rather than at 28 degrees C. In the absence of serum, incubation of infected cultures at 34 degrees C resulted in a significant increase in viral protein and RNA synthesis compared with that observed at 28 degrees C. However, when serum was present in the medium, by 6 h after infection protein synthesis (both host and viral) was markedly inhibited when infected cells were maintained at 34 degrees C. RNA synthesis (host and viral) was also inhibited in vesicular stomatitis virus-infected cells maintained at 34 degrees C with serum, but somewhat more slowly than protein synthesis. Examination of polysome patterns indicated that when infected cultures were maintained under conditions which predispose to CPE, more than half of the ribosomes existed as monosomes, suggesting that protein synthesis was being inhibited at the level of initiation. In addition, the phosphorylation of one (or two) polysome-associated proteins was reduced when protein synthesis was inhibited. Our findings indicate a strong correlation between virus-induced CPE in the LT-C7 clone of A. albopictus cells and the inhibition of protein synthesis. Although the mechanism of the serum effect is not understood, incubation at 34 degrees C probably predisposes to CPE and inhibition of protein synthesis by increasing the amount of viral gene products made.

Sign in / Sign up

Export Citation Format

Share Document