Translational Control of Protein Synthesis in Eat Anterior Pituitary by N-2′-O-dibutyryl adenosine 3′,5′-monophosphate

1973 ◽  
Vol 51 (6) ◽  
pp. 913-919 ◽  
Author(s):  
Roger Boucher ◽  
Marie Gauthier ◽  
Paul Jolicoeur ◽  
Fernand Labrie
Keyword(s):  
Protein Synthesis ◽  
Translational Control ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Short Term ◽  
Nucleotide Pools ◽  
Cytoplasmic Rna ◽  
Nuclear Rna ◽  
Preferential Incorporation ◽  
Stimulation Of

Actinomycin D, at doses (25 and 50 μg/ml) that block RNA synthesis to less than 3% of the control rate, inhibits the incorporation of [3H]leucine into adenohypophyseal proteins and the release of newly synthesized proteins by 50 and 60%, respectively, of the control rates. Despite this lowering of basal levels of total protein synthesis and release in presence of the antibiotic, the percentage of stimulation of both protein synthesis and release by 5 mM N6-2′-O-dibutyryl adenosine 3′5′-monophosphate (dbcAMP) is not depressed by actinomycin D. When rat hemipituitaries are incubated with [3H]uridine, dbcAMP does not stimulate the labeling of total cytoplasmic RNA or the preferential labeling of any cytoplasmic RNA species resolved on sucrose gradient. There is no stimulatory effect of dbcAMP on total labeling or preferential incorporation into nuclear RNA species extracted at 24 °C or at 65 °C. Labeling of the nucleotide pools was unchanged up to 1 h of incubation but was increased (40–70%) during the last [Formula: see text] of incubation. These data suggest that the short-term stimulatory effects of dbcAMP on total adenohypophyseal protein synthesis and release are exerted at the transiational level.

EFFECT OF ACTINOMYCIN D ON TSH-INDUCED STIMULATION OF THYROIDAL PROTEIN SYNTHESIS IN THE RAT

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
The Other ◽  
Leucine Incorporation ◽  
Short Term ◽  
Other Hand ◽  
Thyroid Glands ◽  
Translational Level ◽  
Stimulation Of

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein 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.

Uptake of [3H]Uridine into Precursor Pools and RNA in Osteogenic Cells

1967 ◽  
Vol 2 (1) ◽  
pp. 39-56
Author(s):  
MAUREEN OWEN
Keyword(s):  
Protein Synthesis ◽  
Mammalian Cells ◽  
Rna Synthesis ◽  
Degradation Products ◽  
Cell Types ◽  
Water Soluble ◽  
Radioactive Label ◽  
Cytoplasmic Rna ◽  
Nuclear Rna

Young rabbits were given a single intraperitoneal injection of [3H]uridine. Using the technique of water-soluble autoradiography a study was made of the uptake of the radioactive label into soluble precursors and RNA in cells on an actively growing bone surface. Labelling of the soluble intracellular pools was immediate, but incorporation of label from these pools into RNA was not completed until 24 h after injection. At this time all the label in the sections was in RNA but this represented only 30% of the total label initially in the soluble pools. This means that 70% of the label is lost from the cell in the first 24 h either as degradation products of RNA synthesis or by other as yet unknown mechanisms. The pattern of labelling of the RNA was similar to that previously found for other mammalian cells in vivo or in vitro. There was a rapid uptake of label into nuclear RNA which reached a maximum by 2 h after injection and a slower uptake into cytoplasmic RNA which reached a maximum by 24 h after injection. There was a slow loss of label from the cells after 24 h indicating a half-life of about 8 days for this relatively stable RNA. A comparison was made of RNA synthesis in the proliferating preosteoblasts and the highly differentiated non-dividing osteoblasts. Labelling of the nuclear RNA for the two cell types was identical. The rate of labelling of the cytoplasmic RNA was similar for the two cell types but the maximum level of labelling in the cytoplasm of the osteoblasts was 2 to 3 times that in the preosteoblasts. This could be correlated with the more active protein synthesis by the osteoblasts. There was a slow loss of labelled RNA by the osteoblasts and preosteoblasts and a rapid loss by the osteocytes after the cells had been incorporated within the bone. It was suggested that this loss paralleled the decline in the rate of protein synthesis by the cells as their environment changed.

Rapid effects of insulin on uridine metabolism in mammary gland explants

1975 ◽  
Vol 228 (5) ◽  
pp. 1531-1534 ◽  
Author(s):  
JA Rillema
Keyword(s):  
Protein Synthesis ◽  
Mammary Gland ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Complete Suppression ◽  
Metabolic Fate ◽  
Inhibit Protein Synthesis ◽  
Uridine Uptake ◽  
Rna And Protein Synthesis ◽  
Stimulation Of

A study was made of the early actions of insulin on uridine metabolism in mammary glang explants. A stimulation of both labeled uridine uptake and its incorporation into RNA was demonstrated as early as 15 min after addition of insulin to medium bathing the tissue; these effects persisted for several hours. The metabolic fate of [3-H] uridine to UMP, UDP, and UTP was observed, whereas insulin had no effect on the quantity of 3-H present as uridine or uracil in these tissues. Further studies were performed in which insulin was also shown to have a rapid stimulatory effect on the incorporation of [32-P] phosphate into RNA; however, the uptake of the labeled phosphate was not affected by insulin. Experiments were also carried out to determine whether the effects of insulin on labeled uridine uptake require ongoing RNA and protein synthesis and whether uridine incorporation depends on concomitant protein synthesis. Incubation of explants with antibiotics which inhibit protein synthesis resulted in the complete suppression of the effects of insulin on labeled uridine uptake and its incorporation into RNA. In contrast, the effect of insulin on labeled uridine uptake does not appear to require ongoing RNA synthesis, since this effect persisted when RNA synthesis was significantly reduced by the presence of actinomycin D.

Microsurgical Studies on the Formation of the Golgi Apparatus and Nuclear Envelope in Amebae

1974 ◽  
Vol 32 ◽  
pp. 310-311
Author(s):  
C. J. Flickinger
Keyword(s):  
Protein Synthesis ◽  
Golgi Apparatus ◽  
Nuclear Envelope ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Amoeba Proteus ◽  
Cytoplasmic Protein ◽  
Golgi Bodies ◽  
Nuclear Rna Synthesis ◽  
Nuclear Rna

The means of formation of the Golgi apparatus is uncertain. In beginning these studies, it seemed that an important first step was to determine the degree of dependence of the Golgi apparatus on the nucleus. This was investigated in Amoeba proteus because these cells are readily enucleated microsurgically. Normal amebae contained multiple Golgi bodies, which declined in size and number in the absence of the nucleus, indicating that the Golgi apparatus in amebae depends upon the nucleus. The influence of the nucleus on the Golgi apparatus may be mediated through nuclear RNA synthesis and cytoplasmic protein synthesis, since the ultrastructural effects of enucleation were mimicked by treating amebae with actinomycin D to inhibit RNA synthesis and, in part, by treating cells with emetine, which inhibits protein synthesis in amebae.

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.

scholarly journals Thyroid hormone action in mitochondria

2001 ◽  
Vol 26 (1) ◽  
pp. 67-77 ◽  
Author(s):  
C Wrutniak-Cabello ◽  
F Casas ◽  
G Cabello
Keyword(s):  
Transcription Factor ◽  
Protein Synthesis ◽  
Thyroid Hormone ◽  
Mitochondrial Genome ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Nuclear Gene ◽  
Short Term ◽  
Inner Membrane ◽  
Stimulation Of

Triiodothyronine (T3) is considered a major regulator of mitochondrial activity. In this review, we show evidence of the existence of a direct T3 mitochondrial pathway, and try to clarify the respective importance of the nuclear and mitochondrial pathways for organelle activity. Numerous studies have reported short-term and delayed T3 stimulation of mitochondrial oxygen consumption. Convincing data indicate that an early influence occurs through an extra-nuclear mechanism insensitive to inhibitors of protein synthesis. Although it has been shown that diiodothyronines could actually be T3 mediators of this short-term influence, the detection of specific T3-binding sites, probably corresponding to a 28 kDa c-Erb Aalpha1 protein of the inner membrane, also supports a direct T3 influence. The more delayed influence of thyroid hormone upon mitochondrial respiration probably results from mechanisms elicited at the nuclear level, including changes in phospholipid turnover and stimulation of uncoupling protein expression, leading to an increased inner membrane proton leak. However, the involvement of a direct mitochondrial T3 pathway leading to a rapid stimulation of mitochondrial protein synthesis has to be considered. Both pathways are obviously involved in the T3 stimulation of mitochondrial genome transcription. First, a 43 kDa c-Erb Aalpha1 protein located in the mitochondrial matrix (p43), acting as a potent T3-dependent transcription factor of the mitochondrial genome, induces early stimulation of organelle transcription. In addition, T3 increases mitochondrial TFA expression, a mitochondrial transcription factor encoded by a nuclear gene. Similarly, the stimulation of mitochondriogenesis by thyroid hormone probably involves both pathways. In particular, the c-erb Aalpha gene simultaneously encodes a nuclear and a mitochondrial T3 receptor (p43), thus ensuring coordination of the expression of the mitochondrial genome and of nuclear genes encoding mitochondrial proteins. Recent studies concerning the physiological importance of the direct mitochondrial T3 pathway involving p43 led to the conclusion that it is not only involved in the regulation of fuel metabolism, but also in the regulation of cell differentiation. As the processes leading to or resulting from differentiation are energy-consuming, p43 coordination of metabolism and differentiation could be of significant importance in the regulation of development.

THE EFFECT OF PARATHYROID EXTRACT ON CELLULAR ACTIVITY AND PLASMA CALCIUM LEVELS IN VIVO

1969 ◽  
Vol 45 (3) ◽  
pp. 387-400 ◽  
Author(s):  
PATRICIA J. BINGHAM ◽  
IRIS A. BRAZELL ◽  
MAUREEN OWEN
Keyword(s):  
Rna Synthesis ◽  
Time Lag ◽  
Plasma Calcium ◽  
Cellular Activity ◽  
Maximum Increase ◽  
Cytoplasmic Rna ◽  
Significant Stimulation ◽  
Parathyroid Extract ◽  
Stimulation Of

SUMMARY Parathyroid hormone has a direct effect on the osteoclast population present at the time of administration of the hormone. There was a significant stimulation of nuclear RNA synthesis at the earliest time (1½ hr.) at which the measurement could be made. This is followed by increased production of cytoplasmic RNA which reaches its maximum after a considerable time-lag (7 to 12 hr. after parathyroid extract (PTE)). The increase in cytoplasmic RNA is accompanied by a corresponding stimulation of protein and mucoprotein synthesis in the osteoclasts and the effect persists at least until 24 hr. This time-lag and the relatively long duration of the effect on protein synthesis can be correlated approximately with the effect on the plasma calcium level. It is suggested therefore that the rise in plasma calcium is mainly due to the increased cellular activity of the osteoclasts and the resulting increased bone resorption. The opposite effect on the osteoblast system has about the same time-sequence and would complement the effect on the osteoclast system. At about the same time as the maximum increase in cellular activity in the osteoclasts is observed, a significant effect on RNA synthesis in the endosteal mesenchymal cells, the precursors of the osteoclasts, becomes apparent. This is closely followed by a rise in the number of osteoclasts which is first apparent at 17 hr. after PTE and is maximal by 24 hr. Consequently, the rise in the number of osteoclasts is a secondary effect and is not responsible for the initial rise in plasma calcium which occurred much earlier. It is suggested that the increase in osteoclast numbers follows as a result of the increased metabolic activity of the osteoclast population present when the hormone was injected. There is a depression of RNA synthesis in both the osteoblasts and their precursors, the preosteoblasts. This means that the hormone has opposite effects, not only on the osteoblasts and osteoclasts, but also on their respective precursors, indicating that osteoprogenitor cells contain a mixture of cells with two main lines, those differentiating in an osteoblastic or osteoclastic direction, respectively.

scholarly journals Short-term protein intake and stimulation of protein synthesis in stunted children with cystic fibrosis

2005 ◽  
Vol 81 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Vincent GM Geukers ◽  
Johanna H Oudshoorn ◽  
Jan AJM Taminiau ◽  
Cornelis K van der Ent ◽  
Piet Schilte ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Protein Synthesis ◽  
Protein Intake ◽  
Short Term ◽  
Stimulation Of
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