Changes in protein and nucleic acid synthesis in rat gastric mucosa after pentagastrin.

1977 ◽  
Vol 232 (2) ◽  
pp. E223
Author(s):  
M R Enochs ◽  
L R Johnson
Keyword(s):  
Protein Synthesis ◽  
Gastric Mucosa ◽  
Messenger Rna ◽  
Actinomycin D ◽  
Acid Synthesis ◽  
Secreted Protein ◽  
Macromolecular Synthesis ◽  
Rat Gastric Mucosa ◽  
Ribosomal Rrna ◽  
Stimulation Of

The trophic effects of gastrin on gastrointestinal tissues have been shown to be physiologically important. This study was designed to investigate the sequence of changes in macromolecular synthesis in the rat gastric mucosa following a single dose of pentagastrin. The earliest response was an increase at 1-2 h of poly (A) messenger RNA (mRNA). This increase dropped after 4 h but remained slightly elevated even 12 h after pentagastrin. By 6 h there was a large increase in protein synthesis that lasted until 12 h. Accompanying this rise in protein synthesis was a large increase in ribosomal (rRNA) and transfer RNA (tRNA), which peaked at 12 h. The changes in both fractions of RNA and protein were over by 18 h. No significant increase in secreted protein was noted, but there was a slight, transient decrease at 1 h. Pentagastrin stimulated all forms of RNA, but the largest increase was seen in the rRNA fraction. After multiple doses, parallel increases in rRNA and tRNA were seen. The stimulation of protein synthesis could be abolished by actinomycin D, and was, therefore, RNA dependent.

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.

scholarly journals Regulation of the synthesis of lutropin-induced protein in rat testis Leydig cells

1978 ◽  
Vol 170 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Felix H. A. Janszen ◽  
Brian A. Cooke ◽  
Maria J. A. Van Driel ◽  
Henk J. Van Der Molen
Keyword(s):  
Protein Synthesis ◽  
Cyclic Amp ◽  
Leydig Cells ◽  
Actinomycin D ◽  
Polyacrylamide Gel Electrophoresis ◽  
Phosphodiesterase Inhibitor ◽  
Dibutyryl Cyclic Amp ◽  
Rat Testis ◽  
Stimulation Of

The mechanism of action of lutropin on the stimulation of the synthesis of a specific lutropin-induced protein in rat testis Leydig cells was investigated. Lutropin-induced protein has a mol.wt. of approx. 21000 and is detected by labelling the Leydig-cell proteins with [35S]methionine, followed by separation by polyacrylamide-gel electrophoresis and radioautography of the dried gel. The incorporation of35S into lutropin-induced protein was used as an estimate for the synthesis of the protein. Incubation of Leydig cells with dibutyryl cyclic AMP or cholera toxin also resulted in the stimulation of synthesis of the protein. Synthesis of lutropin-induced protein, when maximally stimulated with 100ng of lutropin/ml, could not be stimulated further by addition of dibutyryl cyclic AMP. Addition of 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, further increased synthesis of the protein in the presence of a submaximal dose of lutropin (10ng/ml) but not in the absence of lutropin or with maximal amounts of lutropin (100 and 1000ng/ml). Actinomycin D prevented the effect of lutropin on the stimulation of lutropin-induced protein synthesis when added immediately or 1h after the start of the incubation, but not when added after 5–6h. This is interpreted as reflecting that, after induction of mRNA coding for lutropin-induced protein, lutropin had no influence on the synthesis of the protein in the presence of actinomycin D. Synthesis of the protein was also stimulated in vivo by injection of choriogonadotropin into rats 1 day after hypophysectomy, and the time course of this stimulation of lutropin-induced protein synthesis in vivo was similar to that obtained by incubating Leydig cells in vitro with lutropin. From these results it is concluded that stimulation of lutropin-induced protein synthesis by lutropin is most probably mediated by cyclic AMP and involves synthesis of mRNA.

Introduction: virus–host interactions

1980 ◽  
Vol 210 (1180) ◽  
pp. 319-320
Keyword(s):  
Protein Synthesis ◽  
Messenger Rna ◽  
Rna Synthesis ◽  
Genetic Material ◽  
Acid Synthesis ◽  
Dna Viruses ◽  
Host Interactions ◽  
Polypeptide Sequence ◽  
Form Part ◽  
Reading Frames

Viruses are among the most extreme parasites, being almost completely dependent upon their host for their growth and replication. Having no intermediary metabolism of their own they make use of the energy supply of the host, its production of nucleoside triphosphates for nucleic acid synthesis and amino acid for protein synthesis, and all of the machinery for protein synthesis. Within the infected cell the virus competes with the host for the supply of all these things and at the same time variants compete among themselves for survival and yield of progeny. It is the intensity of this competition that has produced the most subtle and intimate interactions between virus and host. The need to fit into a protective shell imposes tight limits on the size of the genome in most classes of virus. This means that additional functions can seldom be added simply by adding the necessary genetic information unless there is a compensating loss. But by making more efficient use of the genetic material, additional functions can be accommodated without altering the size of the genome significantly. This is seen to a remarkable degree in the small DNA viruses, where segments of the genome are translated in different reading frames to give different polypeptide sequences and where multiple alternative'splicing in messenger RNA synthesis allows the same polypeptide sequence to form part of two or even three proteins with different properties.

Effect of prolactin on 2-deoxyglucose uptake in mouse mammary gland explants

1992 ◽  
Vol 262 (5) ◽  
pp. E627-E630 ◽  
Author(s):  
B. J. Peters ◽  
J. A. Rillema
Keyword(s):  
Protein Synthesis ◽  
Mammary Gland ◽  
Glucose Uptake ◽  
Glucose Oxidation ◽  
Actinomycin D ◽  
Mouse Mammary Gland ◽  
Temporal Response ◽  
Pregnant Mice ◽  
Glucose Analogue ◽  
Stimulation Of

These studies were carried out to explore the possible effect of prolactin (PRL) on glucose uptake into culture mammary gland explants derived from 12- to 14-day pregnant mice. PRL was found to stimulate an increased rate of uptake of a nonmetabolized glucose analogue, 2-[3H]deoxyglucose, into cultured mammary tissues. The onset of this response was 16 h after the addition of PRL, and the response persisted for at least 24 h. A similar temporal response was observed when the PRL stimulation of [14C]glucose oxidation to 14CO2 was determined. The lowest PRL concentration that elicited a stimulation of 2-deoxyglucose uptake was 20 ng/ml, and a maximum response occurred with PRL at a concentration of 250 ng/ml. Ongoing protein synthesis appears to be essential for PRL to express its effect on 2-deoxyglucose transport since cyclohexamide, puromycin, and actinomycin D abolished the PRL response. It is also apparent that the PRL stimulation of 2-deoxyglucose involves activation of a specific carrier-mediated uptake transport system, since the rate of uptake of L-glucose into mouse mammary gland explants was unaffected by PRL.

Electrically stimulated contraction accelerates protein synthesis rates in adult feline cardiocytes

1993 ◽  
Vol 265 (2) ◽  
pp. H666-H674 ◽  
Author(s):  
C. T. Ivester ◽  
R. L. Kent ◽  
H. Tagawa ◽  
H. Tsutsui ◽  
T. Imamura ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Electrical Stimulation ◽  
Total Protein ◽  
Actinomycin D ◽  
Electrical Field Stimulation ◽  
Cell Protein ◽  
Electrical Field ◽  
Butanedione Monoxime ◽  
H Protein ◽  
Stimulation Of

Cardiocytes were induced to contract via electrical field stimulation with an 8 V/cm electrical square-wave pulse of 5 ms at 0.125-2.0 Hz for up to 6 h. Protein synthesis rates were measured as rate of incorporation of [3H]-phenylalanine into total cell protein. Rates of protein synthesis were accelerated 43 +/- 4%, P < 0.001, by 4 h. The acceleration of total protein synthesis showed a frequency dependence between 0.125 and 0.5 Hz. In addition to accelerating rates of total protein synthesis, electrical stimulation of contraction accelerated fractional rates of synthesis of myosin heavy chain by 42 +/- 8%, P < 0.05. Protein synthesis rates were not accelerated upon electrical stimulation using subthreshold voltages. Addition of 100 ng/ml of actinomycin D had no effect on the ability of electrical stimulation of contraction to accelerate protein synthesis. To uncouple excitation-contraction coupling, 2,3-butanedione monoxime (BDM) was used to block actin-myosin cross-bridge interactions. BDM significantly decreased the ability of electrical stimulation to accelerate protein synthesis rates.

Binding of thyroid hormone to the goat testicular Leydig cell induces the generation of a proteinaceous factor which stimulates androgen release

1994 ◽  
Vol 143 (3) ◽  
pp. 549-556 ◽  
Author(s):  
N R Jana ◽  
S Bhattacharya
Keyword(s):  
Protein Synthesis ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Actinomycin D ◽  
Competitive Inhibition ◽  
Binding Capacity ◽  
Cell Protein ◽  
Scatchard Analysis ◽  
Cell Nuclei ◽  
Stimulation Of

Abstract Leydig cells isolated from goat testis were sonicated and pure nuclear preparations obtained for 125I-3,5,3′-triiodothyronine (T3)-binding assay. Under optimum assay conditions of pH 7·2 at 37 °C and 90 min of incubation, binding of 125I-T3 to Leydig cell nuclei reached saturation at 1·2 nmol/l concentration. A Scatchard analysis of T3 binding exhibited a Kd of 0·535 × 10−9 mol/l and a maximum binding capacity of 1·25 pmol/mg DNA. Competitive inhibition studies showed T3 binding to be analogue specific. The physiological relevance of T3 binding to goat Leydig cell was examined by adding increasing concentrations of T3 to the Leydig cell incubation (1×10 cells/incubation). T3 (10, 25 and 50 ng/ml or 4, 10 and 20 ng/incubation) resulted a dose dependent increase in androgen release and in all cases stimulation of androgen release was statistically significant (P<0·01) compared with control. Stimulation of Leydig cell androgen release by T3 was significantly inhibited by actinomycin-D (P<0·01) and cycloheximide (P<0·01). T3 had additive stimulatory effects on LH-augmented androgen release from Leydig cells. T3 (50 ng/ml or 20 ng/incubation) effected a more than twofold increase in Leydig cell protein synthesis compared with control and both actinomycin-D and cycloheximide (50 μg/ml) inhibited it completely. The data indicated that the stimulatory effect of T3 on androgen release is mediated via T3-induced protein(s). Sub-cellular fractions obtained from T3-treated Leydig cells showed an increase in protein synthesis in mitochondrial and soluble supernatant fractions (100 k sup) and it was only 100 k sup which stimulated androgen release from Leydig cells in separate incubations. Treatment of 100 k sup with trypsin or heat abolished its stimulatory effect. Incubation of Leydig cells with T3 for different times showed an increase in protein synthesis prior to the stimulation of androgen release. The results therefore indicated that T3 binding to Leydig cells induced the generation of a proteinaceous factor(s) which in turn stimulated androgen release. Journal of Endocrinology (1994) 143, 549–556

Stimulation of mucin biosynthesis in rat gastric mucosa by FRG-8813 and its structural analogs

1996 ◽  
Vol 297 (1-2) ◽  
pp. 87-92 ◽  
Author(s):  
Takafumi Ichikawa ◽  
Kazuhiko Ishihara ◽  
Masahiro Shibata ◽  
Tetsuaki Yamaura ◽  
Katsunori Saigenji ◽  
...  
Keyword(s):  
Gastric Mucosa ◽  
Rat Gastric Mucosa ◽  
Stimulation Of
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