scholarly journals The synthesis of ribonucleic acid in immature rat uterus responding to oestradiol-17β

1971 ◽  
Vol 125 (2) ◽  
pp. 605-614 ◽  
Author(s):  
J. T. Knowler ◽  
R. M. S. Smellie
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
Soluble Fraction ◽  
Rat Uterus ◽  
Immature Rat ◽  
Radioactive Precursor ◽  
Major Increase ◽  
Very High ◽  
Time Of Administration ◽  
Stimulation Of

Stimulation of incorporation of labelled precursors into the RNA of immature rat uterus is an early result of oestradiol-17β action. However, the extent of the increased incorporation varies with the mode of administration of the labelled precursors and with the weight of the rat. At the age and weight range normally used response is maximal at ten times control incorporation, 4h after the administration of 0.3μg or more of oestradiol-17β. Under these conditions the stimulation of incorporation into the acid-soluble fraction is only 2–2.5-fold. When the purified RNA is separated on polyacrylamide gels the major increase in incorporation of radioactive precursor is found in rRNA and 4S RNA; the formation of the former has been followed from the 45S precursor. Preceding these events by at least 30min, however, is an increase in the incorporation of precursor into RNA species of very high molecular weight, which remained in the first few slices of the gel. The possible significance of these findings is discussed. The increased synthesis of rRNA in response to oestradiol-17β is more strongly inhibited by actinomycin D than the synthesis of other RNA species. Cycloheximide, depending on time of administration and dosage, inhibits either RNA synthesis or the maturation of rRNA.

scholarly journals Histone acetylation and hormone action. Early effects of oestradiol-17β on histone acetylation in rat uterus

1972 ◽  
Vol 130 (3) ◽  
pp. 663-669 ◽  
Author(s):  
P. R. Libby
Keyword(s):  
Histone Acetylation ◽  
Actinomycin D ◽  
Target Tissue ◽  
Not Given ◽  
Rat Uterus ◽  
Histone Fraction ◽  
Immature Rat ◽  
Chromatin Proteins ◽  
Early Effects ◽  
Stimulation Of

The effect of oestradiol treatment on the acetylation of histones of the immature rat uterus has been studied. A 10μg dose of oestradiol causes a 70% increase at 5min and a 140% increase at 10min after administration in the labelling of the histone fraction F2+F3. No effect of oestradiol is seen on the labelling of histones F1 or acidic non-histone chromatin proteins. The oestradiol stimulation is seen in animals pretreated with either cycloheximide or actinomycin D. The stimulation of labelling caused by oestradiol is completely abolished by pretreatment of the animals with the anti-oestrogen, nafoxidine. The stimulation is given by lower doses of oestradiol, by stilboestrol and oestriol, but is not given by testosterone. These results suggest that stimulation of histone acetylation in the uterus is the earliest known effect of the hormone on its target tissue.

scholarly journals Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Glucose Utilization ◽  
Actinomycin D ◽  
Hormone Synthesis ◽  
Pituitary Glands ◽  
Hormone Biosynthesis ◽  
Stimulation Of

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

STUDIES ON THE MECHANISM OF ACTION OF ANGIOTENSIN ON FLUID TRANSPORT BY THE MUCOSA OF RAT DISTAL COLON

1972 ◽  
Vol 54 (3) ◽  
pp. 483-492 ◽  
Author(s):  
N. T. DAVIES ◽  
K. A. MUNDAY ◽  
B. J. PARSONS
Keyword(s):  
Protein Synthesis ◽  
Cyclic Amp ◽  
Rna Synthesis ◽  
Fluid Transport ◽  
Actinomycin D ◽  
Distal Colon ◽  
Rat Colon ◽  
Colon Mucosa ◽  
Rat Distal Colon ◽  
Stimulation Of

SUMMARY A study was made of the effects of cyclic AMP, theophylline, cycloheximide, puromycin and actinomycin D on the stimulation by angiotensin of fluid transport by sacs of rat colon mucosa. Cyclic AMP and theophylline, added together or separately, had no effect on fluid transport by colon sacs, suggesting that the stimulation of fluid transport after the application of angiotensin is not mediated through cyclic AMP. Cycloheximide and puromycin (used at concentrations which block colon protein synthesis by 50–90%) had no effect on fluid transport by control colon sacs, but completely blocked the stimulatory response of the colon to angiotensin. In contrast, actinomycin D (at a concentration which significantly inhibits RNA synthesis) did not affect fluid transport in control or angiotensin-stimulated colon sacs. The results are discussed in relation to the possibility that protein synthesis, at the stage of translation, is involved in the action of angiotensin on fluid transport by the colon.

STIMULATION OF SYNTHESIS OF GLYCOPROTEIN ENZYMES IN THE RAT UTERUS BY OESTRADIOL

1968 ◽  
Vol 42 (2) ◽  
pp. 261-NP ◽  
Author(s):  
F. A. DUGAN ◽  
B. RADHAKRISHNAMURTHY ◽  
R. A. RUDMAN ◽  
G. S. BERENSON
Keyword(s):  
Total Activity ◽  
Alkaline Phosphatases ◽  
Rat Uterus ◽  
Oestrogen Treatment ◽  
Immature Rat ◽  
Adult Rat ◽  
Electrophoretic Patterns ◽  
Electrophoretic Mobilities ◽  
Hydrolysis Of ◽  
Stimulation Of

SUMMARY Glycoproteins from immature and immature, oestrogen-stimulated and adult rat uteri were isolated and analysed by chemical and gel electrophoretic methods. Esterase, acid phosphatase, alkaline phosphatase and peroxidase activities were found. Changes in electrophoretic mobilities of certain enzyme bands in polyacrylamide gel were also observed after hydrolysis of the preparations with neuraminidase. These latter observations and chemical analyses provide additional evidence of the carbohydrate nature of the enzymes. The influence of 17β-oestradiol on immature rat uteri caused a significant increase in total protein and sialic acid per uterus compared with controls. Oestrogen treatment also resulted in an increase in the total activity of esterase and acid and alkaline phosphatases per uterus, but there was no increase in specific activities. Observations of electrophoretic patterns of glycoprotein preparations from untreated and oestrogen-stimulated, immature uteri did not show the evolution to a more adult pattern by oestrogen stimulation. These studies show that stimulation with oestrogen increases the synthesis of glycoprotein in the immature rat uterus. Factors which are involved in the more intricate control of glycoprotein biosynthesis need to be elucidated.

scholarly journals Changes in the patterns of synthesis of ribonucleic acid species in immature rat uterus in response to oestradiol-17β

1969 ◽  
Vol 112 (5) ◽  
pp. 563-569 ◽  
Author(s):  
R J Billing ◽  
B Barbiroli ◽  
R. M. S. Smellie
Keyword(s):  
Ribosomal Rna ◽  
Hormone Treatment ◽  
Transfer Rna ◽  
Time Intervals ◽  
Rat Uterus ◽  
Immature Rat ◽  
Oestradiol Treatment ◽  
Wet Weight ◽  
Major Increase ◽  
Rna And Dna

1. After treatment of immature rats with diethylstilboestrol, the wet weight and RNA content of uterine tissue increased rapidly, reaching a peak at 40hr. After an initial lag of a few hours, the acid-soluble ribose and protein contents also rose to maxima at 40hr. No increase in DNA content occurred until at least 24hr. after treatment. 2. The RNA from immature rat uterus isolated at various times up to 6hr. after administration of oestradiol-17β was labelled by injecting [3H]uridine and [3H]guanosine intraperitoneally 30min. before the animals were killed. It was fractionated on columns of kieselguhr coated with methylated serum albumin and the radioactivity in fractions corresponding to transfer RNA, 7s RNA, ribosomal RNA, Q1-RNA, Q2-RNA and DNA-like RNA was determined. 3. The radioactivity of the whole RNA increased steadily for 6hr. after hormone treatment. The earliest changes occurred in the Q1-RNA (ribosomal RNA precursor), whereas at longer time-intervals the radioactivity of the ribosomal RNA, 7s RNA and transfer RNA increased by four- to five-fold. The radioactivity of the DNA-like RNA increased by about 50%, but only at the longer time-intervals. 4. It is concluded that one of the earliest changes in response to oestradiol treatment is a major increase in synthesis of ribosomal RNA followed later by a similar increase in synthesis of transfer RNA and by a much smaller increase in synthesis of DNA-like RNA. The change in synthesis of ribosomal RNA in immature rat uterus may represent one of the most important responses to oestradiol treatment.

scholarly journals Comparison of the effects of zinc deprivation and actinomycin D on ribonucleic acid synthesis by stimulated lymphocytes

1975 ◽  
Vol 150 (2) ◽  
pp. 211-218 ◽  
Author(s):  
J K Chesters
Keyword(s):  
Actinomycin D ◽  
Soluble Fraction ◽  
Acid Synthesis ◽  
28S Rrna ◽  
Similar Time ◽  
Uridine Incorporation ◽  
Low Concentrations ◽  
Time Courses ◽  
Polymerase I ◽  
Stimulation Of

1. EDTA inhibited incorporation of [3H]uridine into RNA of lymphocytes, but did not decrease uptake into the cold-acid-soluble fraction of the cells. The inhibition by EDTA was largely reversible by simultaneous addition of Zn2+. 2. Low concentrations pf actinomycin D (3 ng/ml) added at the time of stimulation of the cells inhibited [3H]uridine incorporation into RNA, but concentrations of 50-100 ng/ml were required to produce the same degree of inhibition if addition of actinomycin D was delayed until just before the incorporation was measured. This difference in sensitivity did not reg within the cells. 3. When added immediately before phytohaemagglutinin, actinomycin D (3 ng/ml) and EDTA produced similar time-courses of inhibition of uridine incorporation. 4. Uridine incorporation at 32h was inhibited when actinomycin D (3 ng/ml) or EDTA was added just before stimulation of the cells, but was only slightly affected when they were added at 32h. At intermediate times the incorporation of uridine remained sensitive to addition of EDTA for longer than it was sensitive to actinomycin D. 5. Polyacrylamide-gel separation of RNA synthesized in EDTA-treated cultures in the presence or absence of added Zn2+ showed that lower availability of Zn2+ resulted in a decreased rate of transfer of radioactivity from 32S to 28S rRNA and decreased survival of 28S rRNA relative to 18S rRNA. 6. Close similarities have been shown to exist between the effects of EDTA and low concentrations of actinomycin D. Not all the effects of EDTA could be explained by postulating that Zn2+ was a constituent of RNA polymerase I, nor were the effects of actinomycin D readily explained by previously suggested mechanisms of action of this antibiotic.

FIBRIN STIMULATION OF ENDOTHELIAL CELL (EC) PRODUCTION OF PGI AND TISSUE PLASMINOGEN ACTIVATOR (t-PA)

1987 ◽  
Author(s):  
L K Kaplan ◽  
T Mather ◽  
L DeMarco ◽  
S Solomon
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
Umbilical Vein ◽  
Cytochalasin D ◽  
Time Dependent ◽  
Time Intervals ◽  
Tissue Plasminogen ◽  
Protein And Rna Synthesis ◽  
Maximal Production ◽  
Stimulation Of

Many substances are known to stimulate EC production of PGI2 and t-PA. Additionally, it has been reported that fibrin can Be formed on the EC surface. In this study, the possibility that fibrin generated on the surface of cells can stimulate production of PGI2 and t-PA was examined. Human umbilical vein ECs were incubated for various time intervals with citrated human plasma clotted on the cells by the addition of CaCl2 . Control dishes contained plasma without Ca++ or serum. Time-dependent generation of PGI2 and t-PA was seen over 22-24 hours. Maximal production of PGI2 occurred when fibrin on the cells was formed from 10 to 50% plasma, with serum comprising the remainder of the incubation volume, while maximal t-PA production occurred with clots formed from 100% plasma. Fibrin I formed by addition of batroboxin to citrated plasma stimulated less synthesis of t-PA than did fibrin formed by thrombin action, and it did not stimulate PGI2 production. Thrombin clots were significantly more adherent to the cells than were batroboxin clots. PG^ synthesis induced by fibrin was fully inhibited by indomethacin, approximately 50% inhibited by actinomycin D and cycloheximide, and 20% inhibited by trifluoperazine, but was unaffected by cytochalasin D and vinblastine. Stimulation of t-PA synthesis by fibrin was unaffected by indomethacin, completely inhibited by actinomycin D and cycloheximide, and 60%, 80% and 40% blocked by cytochalasin D, vinblastine, and trifluoperazine, respectively. Thus, thrombin-induced fibrin clots stimulated PGI2 synthesis, and both thrombin and batroboxin clots stimulated t-PA synthesis. Protein and RNA synthesis were essential to stimulation of t-PA synthesis but inhibition of these processes only partially inhibited stimulation of PGI2 synthesis. Integrity of the cytoskeleton was necessary for full stimulation of t-PA synthesis, but not for stimulation of PGI2 synthesis. Thus the mechanisms of stimulation of these two cellular products were different. Increased PGI2 production could serve to limit further fibrin formation by preventing platelets from contributing to the coagulation process and increased t-PA could stimulate lysis of existing fibrin.

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