scholarly journals Re-utilization of pyrimidine nucleotides during rat liver regeneration

1985 ◽  
Vol 228 (1) ◽  
pp. 27-33 ◽  
Author(s):  
E N Nikolov ◽  
M D Dabeva
Keyword(s):  
Rat Liver ◽  
Rna Degradation ◽  
Total Acid ◽  
Pyrimidine Nucleotides ◽  
True Rate ◽  
Cytoplasmic Rna ◽  
Nuclear Rna ◽  
Rat Liver Cells ◽  
Ribonucleoside Triphosphate ◽  
Uridine Nucleotides

The changes in the specific radioactivities of the pool of total acid-soluble uridine nucleotides and of uridine and cytidine components of total cellular and nuclear RNA were monitored in regenerating rat liver for 12 days after partial hepatectomy. Evidence is presented for the re-utilization of pyrimidine nucleotides derived from cytoplasmic RNA degradation for the synthesis of new RNA. The extent of recycling was assessed and the true rate of rRNA turnover determined more accurately. The reutilization of the uridine components of RNA was 7.0%/day during the proliferative and 3.2%/day during the post-proliferative phase, whereas that of the cytidine nucleotides was more pronounced (9.6%/day and 18.1%/day respectively). The results reveal the existence of partial compartmentalization of pyrimidine ribonucleoside triphosphate pools in the nucleus and cytoplasm of rat liver cells.

Isolation from rat liver cells of a nuclear RNA fraction having messenger activity

Life Sciences ◽  
1964 ◽  
Vol 3 (3) ◽  
pp. 161-167 ◽  
Author(s):  
Norbert Lang ◽  
Constantin E. Sekeris
Keyword(s):  
Rat Liver ◽  
Liver Cells ◽  
Nuclear Rna ◽  
Rat Liver Cells

scholarly journals Inhibition of gluconeogenesis in isolated rat liver cells by methylenecyclopropylpyruvate (ketohypoglycin)

1979 ◽  
Vol 182 (3) ◽  
pp. 789-796 ◽  
Author(s):  
E A Kean ◽  
C I Pogson
Keyword(s):  
Rat Liver ◽  
Liver Cells ◽  
Relative Increase ◽  
Total Acid ◽  
Isolated Rat Liver ◽  
Rat Liver Cells ◽  
Chain Acyl ◽  
Beta Hydroxybutyrate ◽  
Isolated Rat ◽  
Pyruvate Ratio

1. In isolated rat liver cells, hypoglycin is a less effective inhibitor of gluconeogenesis than its transamination product, methylenecyclopropylpyruvate (ketohypoglycin). 2. Methylenecyclopropylpyruvate at 0.3 mM inhibits gluconeogenesis from all substrates tested, except fructose. 3. Methylenecyclopropylpyruvate does not affect 14CO2 release from [1(-14)C]palmitate, but, in the absence of lactate, inhibits ketogenesis and causes a decrease in the [beta‐hydroxybutyrate]/[acetoacetate] ratio. These effects are masked when lactate (10 mM) is present. 4. In the presence of lactate and palmitate, 0.3 mM-methylenecyclopropylpyruvate produces a fall in total acid-soluble CoA and a relative increase in short-chain acyl-CoA at the expense of CoA and acetyl-CoA without changing the ATP, ADP and aspartate contents or the [lactate]/[pyruvate] ratio. 5. Many of the effects of methylenecyclopropylpyruvate observed are consistent with inhibition of butyryl-CoA dehydrogenase and of specific CoA-dependent enzymes involved in gluconeogenesis.

scholarly journals Fractionation of nuclear and cytoplasmic ribonucleic acids from rat tissues on the methylated albumin–kieselguhr column

1971 ◽  
Vol 125 (1) ◽  
pp. 225-234 ◽  
Author(s):  
A. V. Lichtenstein ◽  
V. S. Shapot
Keyword(s):  
Rat Liver ◽  
Selective Adsorption ◽  
Resolving Power ◽  
Rat Tissues ◽  
Preparative Scale ◽  
Ribonucleic Acids ◽  
Cytoplasmic Rna ◽  
Special Procedure ◽  
Cytoplasmic Dna ◽  
Nuclear Rna

1. The conformation of RNA was found to affect its behaviour on methylated albumin–kieselguhr chromatography. The less regular the secondary structure of RNA, the more tightly it binds to the methylated albumin–kieselguhr column. 2. The presence of various denaturing agents (such as urea or perchlorate) in the medium while RNA was adsorbed on the column increased the resolving power of the technique as exemplified by the separation of rat liver rRNA into two distinct peaks. A special procedure for selective adsorption of the cytoplasmic DNA-like RNA on the preparative scale has been developed. Polyribosomal mRNA (rapidly labelled RNA formed in the presence of small doses of actinomycin D) can also be adsorbed selectively by the column. 3. A type of tissue specificity was detected in nuclear RNA from rat liver, kidney, thymus and spleen by using a modified salt and temperature gradient for the chromatographic fractionation (Lichtenstein, Piker & Shapot, 1967; Shapot, Lichtenstein & Piker, 1967). It was also found that cytoplasmic RNA from the different rat tissues contained no tenaciously bound fraction at all, whereas it constituted about 50% of the nuclear RNA. The problem of the possible biological function of the tenaciously bound fraction is discussed.

Effects of Hypophysectomy on the Fine Structure of Rat Liver Cells

1967 ◽  
Vol 25 ◽  
pp. 156-157
Author(s):  
Robert R. Cardell
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Rat Liver ◽  
Liver Cell ◽  
Anterior Pituitary ◽  
Liver Cells ◽  
Biochemical Studies ◽  
Liver Functions ◽  
Rat Liver Cells ◽  
And Control

Hypophysectomy of the rat renders this animal deficient in the hormones of the anterior pituitary gland, thus causing many primary and secondary hormonal effects on basic liver functions. Biochemical studies of these alterations in the rat liver cell are quite extensive; however, relatively few morphological observations on such cells have been recorded. Because the available biochemical information was derived mostly from disrupted and fractionated liver cells, it seemed desirable to examine the problem with the techniques of electron microscopy in order to see what changes are apparent in the intact liver cell after hypophysectomy. Accordingly, liver cells from rats which had been hypophysectomized 5-120 days before sacrifice were studied. Sham-operated rats served as controls and both hypophysectomized and control rats were fasted 15 hours before sacrifice.

Heterogeneity of carboxylesterases in rat liver cells

1992 ◽  
Vol 44 (4) ◽  
pp. 827-829 ◽  
Author(s):  
Rolf Gaustad ◽  
Trond Berg ◽  
Frode Fonnum
Keyword(s):  
Rat Liver ◽  
Liver Cells ◽  
Rat Liver Cells
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