Effects of X-radiation on thymidine incorporation and deoxyribonucleoprotein integrity in rat tissues

1969 ◽  
Vol 47 (11) ◽  
pp. 1003-1006 ◽  
Author(s):  
D. K. Myers ◽  
S. Ram
Keyword(s):  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Thymidine Incorporation ◽  
Rat Tissues ◽  
Lethal Effects ◽  
Early Effect ◽  
Inhibition Of Dna Synthesis ◽  
Postradiation Period ◽  
Observation Period

The early effect of X-radiation on thymidine incorporation into deoxyribonucleic acid (DNA) did not differ markedly in rat tissues which are resistant and those which are sensitive to the lethal effects of irradiation. Inhibition of DNA synthesis was accompanied by loss of integrity of deoxyribonucleoprotein (DNAP) in all tissues examined during the postradiation period. The cells of radioresistant tissues were able to repair the postradiation damage to DNAP, while the degradation of DNAP continued unchecked in radiosensitive tissues during a 24-h observation period.

Influence of food deprivation and adrenal steroids on DNA synthesis in various mammalian tissues

1975 ◽  
Vol 228 (1) ◽  
pp. 310-317 ◽  
Author(s):  
AL Goldberg ◽  
DF Goldspink
Keyword(s):  
Dna Synthesis ◽  
Food Deprivation ◽  
Thymidine Incorporation ◽  
Normal Growth ◽  
Adrenal Steroids ◽  
Muscle Weight ◽  
Mammalian Tissues ◽  
Influence Of Food ◽  
Inhibition Of Dna Synthesis ◽  
Fasted Rats

The DNA content of skeletal muscle increases as young rats grow. Food deprivation prevented this increase: total DNA remained constant, while muscle weight and RNA decreased. Diaphragms isolated from fasted rats incorporated [3H]thymidine into DNA far more slowly than tissues from fed rats. Incorporation returned to control levels on refeeding. Fasting for 24 or 48 h also markedly reduced [3H]thymidine incorporation by slices of liver, kidney, and brain. The factors responsible for this inhibition of DNA synthesis were investigated. Amino acids, insulin, or serum from fed or fasted rats failed to alter thymidine incorporation by muscle. Injection of hydrocortisone into normal rats reduced incorporation into kidneys, liver, and muscle within 4h. Incubation of hemidiaphragms with hydrocortisone suppressed [3H]thymidine incorporation within 2-3h. Adrenalectomy enhanced incorporation into DNA by diaphragm, liver, kidney, and brain. When fasted, adrenalectomized rats showed little or no suppression of [3H]thymidine incorporation and lost less weight than fasted controls. These data suggest that adrenal steroids are important in inhibiting DNA synthesis during normal growth and during fasting.

Nuclear Ultrastructure of the Transforming Lymphocyte during Inhibition of Deoxyribonucleic Acid Synthesis with Hydroxyurea

1969 ◽  
Vol 4 (3) ◽  
pp. 583-591
Author(s):  
GILLIAN R. MILNER
Keyword(s):  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Metabolic Inhibition ◽  
Nuclear Ultrastructure ◽  
Deoxyribonucleic Acid Synthesis ◽  
Inhibition Of Dna Synthesis

The pattern of decondensation of heterochromatin in the transforming lymphocyte was found to be unaffected by hydroxyurea although DNA synthesis, which normally accompanies the latter part of this decondensation, was greArticleTitley inhibited. It is suggested that metabolic inhibition of DNA synthesis may result in atypical sites of DNA synthesis when the inhibitor is removed, since such sites are normally partly governed by an ordered sequence of decondensation of heterochromatin.

scholarly journals Inhibition of DNA synthesis in adrenocortical cells by cytochalasin B.

1980 ◽  
Vol 86 (1) ◽  
pp. 129-134 ◽  
Author(s):  
M A McPherson ◽  
J Ramachandran
Keyword(s):  
Dna Synthesis ◽  
Cytochalasin B ◽  
Thymidine Incorporation ◽  
Cell Types ◽  
Mouse Tumor ◽  
Adrenocortical Cells ◽  
Normal Cells ◽  
Normal Rat ◽  
Thymidine Transport ◽  
Inhibition Of Dna Synthesis

ACTH inhibits DNA synthesis in normal rat and mouse tumor Y-1 adrenocortical cells within the same concentration range that it stimulates steroidogenesis. These processes can be independently regulated as demonstrated by the divergent actions of cytochalasin B on these cells. In the normal cells, cytochalasin B does not increase steroidogenesis in serum-free or serum-containing media, and it decreases the stimulation produced by ACTH. In the absence of serum, the Y-1 cells respond in a similar way. However, in serum-containing media, cytochalasin B increases steroidogenesis in these cells and does not inhibit the response to ACTH. In both cell types, cytochalasin B inhibits [3H]thymidine incorporation into DNA by a mechanism different than that of ACTH. In the Y-1 cells, this inhibition is caused by a decreased uptake of [3H]thymidine into the cell, which probably reflects a decreased transport across the cell membrane. In the normal cells, cytochalasin B, like ACTH, does not affect [3H]thymidine transport, but it decreases DNA synthesis much more rapidly than does ACTH. This inhibition may be the result of the disruption of microfilaments by cytochalasinB, because our evidence indicates that it is not caused by a decrease in glucose uptake by the cells.

Methylation of Deoxyribonucleic Acid in Regenerating Rat Liver

1973 ◽  
Vol 28 (7-8) ◽  
pp. 463-465
Author(s):  
Dieter Lutz ◽  
Helga Grahn ◽  
Hans Kröger
Keyword(s):  
Dna Methylation ◽  
Dna Synthesis ◽  
Partial Hepatectomy ◽  
Rat Liver ◽  
Deoxyribonucleic Acid ◽  
Thymidine Incorporation ◽  
Regenerating Rat Liver ◽  
Double Label

In double label pulse experiments DNA methylation was compared to DNA synthesis after partial hepatectomy. 24 hours after the operation the highest 14C-thymidine incorporation rates were found as well as the highest 5-methylcytosine labelling derived from (3H-methyl) -methionine. However, synthesis was much more elevated than DNA methylation. Applying Endoxan DNA methylation is reduced to a significantly higher extent than DNA synthesis. Our results indicate that DNA methylation occurs not only combined with DNA synthesis.

scholarly journals Inhibition of DNA synthesis in living cells by microinjection of Gi2 antibodies.

1992 ◽  
Vol 267 (2) ◽  
pp. 691-694 ◽  
Author(s):  
V J LaMorte ◽  
P K Goldsmith ◽  
A M Spiegel ◽  
J L Meinkoth ◽  
J R Feramisco
Keyword(s):  
Dna Synthesis ◽  
Living Cells ◽  
Inhibition Of Dna Synthesis

scholarly journals Involvement of deoxyribonucleic acid polymerase β in nuclear deoxyribonucleic acid synthesis

1978 ◽  
Vol 173 (1) ◽  
pp. 309-314 ◽  
Author(s):  
T R Butt ◽  
W M Wood ◽  
E L McKay ◽  
R L P Adams
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Deoxyribonucleic Acid ◽  
Nuclear Dna ◽  
Dna Polymerase Beta ◽  
Cell Nuclei ◽  
High Molecular Weight Dna ◽  
Dna Polymerase Alpha ◽  
Polymerase Beta

The effects on DNA synthesis in vitro in mouse L929-cell nuclei of differential extraction of DNA polymerases alpha and beta were studied. Removal of all measurable DNA polymerase alpha and 20% of DNA polymerase beta leads to a 40% fall in the replicative DNA synthesis. Removal of 70% of DNA polymerase beta inhibits replicative synthesis by 80%. In all cases the nuclear DNA synthesis is sensitive to N-ethylmaleimide and aCTP (arabinosylcytosine triphosphate), though less so than DNA polymerase alpha. Addition of deoxyribonuclease I to the nuclear incubation leads to synthesis of high-molecular-weight DNA in a repair reaction. This occurs equally in nuclei from non-growing or S-phase cells. The former nuclei lack DNA polymerase alpha and the reaction reflects the sensitivity of DNA polymerase beta to inhibiton by N-ethylmaleimide and aCTP.

A STUDY OF BLASTOCYSTS DURING DELAY AND SUBSEQUENT IMPLANTATION IN LACTATING MICE

1968 ◽  
Vol 42 (3) ◽  
pp. 453-463 ◽  
Author(s):  
ANNE McLAREN
Keyword(s):  
Dna Synthesis ◽  
Thymidine Incorporation ◽  
Tritiated Thymidine ◽  
Uterine Horn ◽  
Uterine Epithelium ◽  
Serial Sections ◽  
Uterine Lumen ◽  
Fresh State

SUMMARY Blastocysts were studied on the 5th and 8th day of pregnancy in lactating mice, in the fresh state, flushed from the uterus, in squash preparations and in serial sections. At the earlier period some mitosis was observed. Tritiated thymidine incorporation studies gave some evidence of DNA synthesis on the 5th and 6th days of pregnancy. By the 8th day the blastocysts were longer, contained more cells, and mitosis had ceased. They were located at the anti-mesometrial end of the uterine lumen, closely apposed to the uterine epithelium, and with their long axes parallel to the long axis of the uterine horn. Implantation could be induced, either by the removal of the litter, or by the injection of an appropriate dose of oestrogen on the 5th or 7th (but not the 4th) day of pregnancy. Both treatments were followed by the appearance of W-bodies in the neighbourhood of the blastocysts, the disappearance of the shed zonae, and the appearance of Pontamine Blue reactivity, oedema of the uterine stroma and formation of the primary decidual zone, in that order.

The effect of ara-C-induced inhibition of DNA synthesis on its cellular pharmacology

1990 ◽  
Vol 25 (6) ◽  
pp. 418-424 ◽  
Author(s):  
Li-Ming Wang ◽  
J. Courtland White ◽  
Robert L. Capizzi
Keyword(s):  
Dna Synthesis ◽  
Cellular Pharmacology ◽  
Inhibition Of Dna Synthesis
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