Effect of Tumour Growth on Hepatic Neutral Ribonuclease and Its Inhibitor and on RNA Polymerase Activity of Liver Nuclei

Enzyme ◽  
1983 ◽  
Vol 30 (4) ◽  
pp. 239-243 ◽  
Keyword(s):  
Rna Polymerase ◽  
Tumour Growth ◽  
Polymerase Activity ◽  
Rna Polymerase Activity ◽  
Liver Nuclei

scholarly journals Studies on ribonucleic acid and homopolyribonucleotide formation in neuronal, glial and liver nuclei

1970 ◽  
Vol 116 (4) ◽  
pp. 599-609 ◽  
Author(s):  
Takahiko Kato ◽  
Masanori Kurokawa
Keyword(s):  
White Matter ◽  
Guinea Pig ◽  
Rna Polymerase ◽  
Grey Matter ◽  
Polymerase Activity ◽  
Physical Relationship ◽  
Neuronal Nuclei ◽  
Cerebral Grey Matter ◽  
Rna Polymerase Activity ◽  
Liver Nuclei

1. Various types of nuclear preparations, with different ratios of neuronal to glial nuclei, were isolated from guinea-pig cerebral grey matter and ox cerebral grey matter and white matter. Conditions appropriate for the separate assay of RNA and poly A formation were described. Comparative rates of RNA and poly A formation were studied in cerebral and liver nuclei. 2. RNA polymerase activity per nucleus is higher in neuronal nuclei than in glial nuclei. In liver nuclei, the activity is much lower than in cerebral nuclei. The physical relationship between RNA polymerase and deoxyribonucleoprotein seems to differ in neuronal, glial and liver nuclei. 3. Poly A polymerase activity in liver nuclei is selectively activated by Mn2+ and inhibited by GTP, CTP and UTP. On a DNA basis, the activity in an aggregate enzyme is the same as in intact nuclei. Poly A polymerase activity per nucleus is much higher in liver nuclei than in neuronal nuclei. Glial nuclei show an intermediate activity. 4. It is suggested that, in neuronal nuclei, the synthesis of RNA is more prominent than that of poly A under conditions where both polymers are formed simultaneously. This contrasts with liver nuclei, where more poly A is made than RNA. 5. In neuronal nuclei, the rate of CTP incorporation is much higher than in glial and liver nuclei. This incorporation is most probably due to poly C synthesis.

scholarly journals Effect of hypophysectomy on liver nuclear ribonucleic acid synthesis in aging rats

1979 ◽  
Vol 184 (3) ◽  
pp. 669-674 ◽  
Author(s):  
R Bolla ◽  
W D Denckla
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Hormone Replacement ◽  
Polymerase Activity ◽  
Sprague Dawley ◽  
Age Related ◽  
Nuclear Rna ◽  
Rna Polymerase Activity ◽  
Liver Nuclei ◽  
Intact Rats

Changes in RNA synthesis in liver nuclei were observed at different ages and after hypophysectomy and hormone replacement in female Sprague-Dawley rats. As determined by the incorporation of [3H]UMP into an acid-insoluble product, RNA synthesis decreased by about 75% in intact rats from 6 months to 24 months of age. This decline with age was not observed in liver nuclei from 24-month-old rats that had been hypophysectomized at 12 months and maintained on a minimal hormone-replacement therapy. Thyroid hormones and somatotropin (growth hormone) had an additive effect on RNA synthesis in liver nuclei from these hypophysectomized rats. The same hormones had no significant effect on intact, age-matched rats. With advancing age, nuclei of intact rats had an increase in the pool of free RNA polymerase and an apparent decrease in the enzyme activity bound to nuclear chromatin. There was no change in total enzyme with age. In hypophysectomized, hormone-treated rats, free RNA polymerase activity decreased and chromatin-bound activity increased. There was no difference in total nuclear RNA polymerase activity between operated or intact rats. However, the ratio of the bound to the free activity was different. These results suggest that the ability of RNA polymerase to bind to chromatin may be involved in the age-related decrease in liver nuclear RNA synthesis of intact rats.

A Possible Role of Lipids in RNA Polymerase from Mammalian Cells

1972 ◽  
Vol 50 (7) ◽  
pp. 807-812 ◽  
Author(s):  
I. A. Menon
Keyword(s):  
Rna Polymerase ◽  
Phospholipase D ◽  
Mammalian Cells ◽  
Polymerase Activity ◽  
Ionic Concentration ◽  
Phospholipase A ◽  
Rat Tissues ◽  
Rna Polymerase Activity ◽  
Liver Nuclei

The effects of treatment with phospholipases and extraction with solvents on the activities of RNA polymerases from several rat tissues were studied. The RNA polymerase activity of particulate enzyme from rat liver nuclei was decreased by pretreatment of the enzyme with phospholipase A. The phospholipase decreased the RNA polymerase activity in presence of Mg2+ but not that in presence of Mn2+. The effect of phospholipase A was observed only at low ionic concentration. When the RNA polymerase activity was determined in presence of ammonium sulfate, KCl, or NaCl, phospholipase A did not decrease the RNA polymerase activity. Extraction of the RNA polymerase with ether or iso-octane decreased the RNA polymerase activity to approximately the same extent as the pretreatment with phospholipase A. Phospholipase C produced similar changes as phospholipase A but phospholipase D and lipase did not have any effect on the RNA polymerase activity. Treatment with phospholipase A as well as extraction with solvents enhanced the activity of chromatin-bound RNA polymerase from rat brain, and the RNA polymerase activities of similar preparations from spleen, kidney, heart, and lung were affected only to a relatively smaller extent.

scholarly journals Stimulating Effect of Panax ginseng Extract on RNA Polymerase Activity in Rat Liver Nuclei

1971 ◽  
Vol 19 (8) ◽  
pp. 1656-1663 ◽  
Author(s):  
SUSUMU HIAI ◽  
HIKOKICHI OURA ◽  
KINJI TSUKADA ◽  
YOSHIKATSU HIRAI
Keyword(s):  
Rna Polymerase ◽  
Panax Ginseng ◽  
Rat Liver ◽  
Polymerase Activity ◽  
Ginseng Extract ◽  
Rat Liver Nuclei ◽  
Rna Polymerase Activity ◽  
Liver Nuclei
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