Insulin stimulation of protein synthesis in cultured skeletal and cardiac muscle cells

1982 ◽  
Vol 243 (1) ◽  
pp. C81-C86 ◽  
Author(s):  
J. Airhart ◽  
J. A. Arnold ◽  
W. S. Stirewalt ◽  
R. B. Low
Keyword(s):  
Protein Synthesis ◽  
Specific Activity ◽  
Muscle Cells ◽  
Cell Types ◽  
Cardiac Cells ◽  
Cardiac Muscle Cells ◽  
Significant Stimulation ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
Stimulation Of

The effects of acute exposure to insulin on protein synthesis were examined in primary, differentiated cultures of embryonic chick heart and skeletal muscle cells. Synthetic rates were calculated using the specific activity of tRNA-bound leucine as precursor, a specific activity that was significantly less than that of extracellular leucine but greater than that of free, intracellular leucine at 0.2 mM external leucine. Insulin did not alter these relationships. Doses of insulin in the physiological range produced significant stimulation of protein synthesis in both cell types. Maximal responses, involving approximately 30% increases in both absolute and fractional rates, were observed at higher insulin concentrations. Significant stimulation by insulin was seen in cardiac cells after only 1 h of insulin treatment, and the effects of the hormone were observed both in the presence and absence of serum in the culture medium.

Stimulation of transport of alpha-aminoisobutyric acid into the testes of immature mice in vivo by follicle-stimulating hormone

1982 ◽  
Vol 100 (1) ◽  
pp. 137-142
Author(s):  
Nila Oza ◽  
Sarah J. Meanock ◽  
A. G. Davies
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Specific Activity ◽  
Follicle Stimulating Hormone ◽  
Acid Transport ◽  
Aminoisobutyric Acid ◽  
Old Mice ◽  
Stimulation Of

Abstract. Groups of immature mice were injected sc with radiocarbon-labelled alpha-aminoisobutyric acid (AIB) after being given a single sc injection of hFSH or of 0.9% saline. As an index of the transport of AIB, the specific activity of isotope was measured in homogenates of testis and of liver. FSH treatment caused statistically significant increases in the specific activity of isotope in the testes and in the ratio of testicular to liver specific activity. The effect was greatest in 9-day-old mice injected with FSH 16 h before removal of the testes. Uptake of labelled AIB was not stimulated after administration of hCG or testosterone. Doses of cycloheximide sufficient to reduce the rate of protein synthesis by over 99% did not impair testicular uptake of labelled AIB or the influence of FSH on AIB uptake. These results suggest that FSH stimulates amino acid transport into cells of the immature testis and that this action is independent of the stimulatory effect of FSH on testicular protein synthesis.

Glucose-dependent stimulation of protein synthesis in cultured heart muscle cells

FEBS Letters ◽  
1980 ◽  
Vol 119 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Katy Ravid ◽  
Paula Diamant ◽  
Y. Avi-Dor
Keyword(s):  
Protein Synthesis ◽  
Heart Muscle ◽  
Muscle Cells ◽  
Heart Muscle Cells ◽  
Stimulation Of

Effects of caffeine on the DNA and protein synthesis of the protein-energy malnourished neonatal cardiac muscle cells in culture

1992 ◽  
Vol 23 (3) ◽  
pp. 385-389 ◽  
Author(s):  
Yoshifumi Kanemaru ◽  
Magdalena J. Rossowska ◽  
Shoichi Yoshino ◽  
Malektaj Yazdani ◽  
C.H. Narayanan ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Cardiac Muscle ◽  
Muscle Cells ◽  
Cardiac Muscle Cells ◽  
Cells In Culture ◽  
Protein Energy ◽  
Dna And Protein Synthesis

Overdrive suppression of automaticity in cultured chick myocardial cells

1980 ◽  
Vol 238 (1) ◽  
pp. H24-H30 ◽  
Author(s):  
A. Pelleg ◽  
S. Vogel ◽  
L. Belardinelli ◽  
N. Sperelakis
Keyword(s):  
Heart Cells ◽  
Spontaneous Firing ◽  
Embryonic Chick ◽  
Quiescent Cells ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
Overdrive Suppression ◽  
Time Courses ◽  
Spontaneous Firing Rate ◽  
Stimulation Of

Overdrive suppression in automatic cells and postdrive hyperpolarization in quiescent cells were examined in cultured embryonic chick heart cells. Cells were enzymatically separated from 3-day-old whole hearts and from 16-day-old atria and ventricles. The dispersed cells were allowed to reaggregate into small spheres (aneural) and maintained in culture for 1--4 wk. Quiescent reaggregates (all ventricular reaggregates and some of the atrial) demonstrated postdrive transient hyperpolarization of up to 5 mV. The spontaneously beating reaggregates (some of the atrial and all of the 3-day-old hearts) demonstrated overdrive suppression of automaticity. The faster the predrive spontaneous firing rate, the shorter was the overdrive suppression period. Prolongation of the drive period increased the duration of the overdrive suppression. The time courses of recovery from both overdrive suppression and postdrive hyperpolarization were similar. Atropine (10(-5) M) did not affect the phenomena. Ouabain (10(-6) M) reduced the postdrive hyperpolarization and shortened the duration of overdrive suppression. It was concluded that overdrive suppression and postdrive hyperpolarization a) occur in cultured chick ventricular and atrail cells; b) occur in early embryonic stages of development; c) occur independently of cholinergic receptors; d) are dependent on stimulation of an elecrogenic Na-K pump.

scholarly journals Raf-1 Activation Prevents Caspase 9 Processing Downstream of Apoptosome Formation

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Sébastien Cagnol ◽  
Anna Mansour ◽  
Ellen Van Obberghen-Schilling ◽  
Jean-Claude Chambard
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Cytochrome C ◽  
Protective Effect ◽  
Gel Filtration ◽  
Cell Types ◽  
Protective Mechanism ◽  
Caspase 9 ◽  
Chromatography Analysis ◽  
Stimulation Of

In many cell types, growth factor removal induces the release of cytochrome-c from mitochondria that leads to activation of caspase-9 in the apoptosome complex. Here, we show that sustained stimulation of the Raf-1/MAPK1,3 pathway prevents caspase-9 activation induced by serum depletion in CCL39/Raf-1:ER fibroblasts. The protective effect mediated by Raf-1 is sensitive to MEK inhibition that is sufficient to induce caspase-9 cleavage in exponentially growing cells. Raf-1 activation does not inhibit the release of cytochrome-c from mitochondria while preventing caspase-9 activation. Gel filtration chromatography analysis of apoptosome formation in cells shows that Raf-1/MAPK1,3 activation does not interfere with APAF-1 oligomerization and recruitment of caspase 9. Raf-1-mediated caspase-9 inhibition is sensitive to emetine, indicating that the protective mechanism requires protein synthesis. However, the Raf/MAPK1,3 pathway does not regulate XIAP. Taken together, these results indicate that the Raf-1/MAPK1,3 pathway controls an apoptosis regulator that prevents caspase-9 activation in the apoptosome complex.

scholarly journals Stimulation of protein synthesis in cultured heart muscle cells by glucose

1975 ◽  
Vol 150 (3) ◽  
pp. 405-411 ◽  
Author(s):  
M David ◽  
Y Avi-Dor
Keyword(s):  
Protein Synthesis ◽  
Heart Muscle ◽  
Muscle Cells ◽  
Inhibitory Effect ◽  
Insoluble Fraction ◽  
Leucine Incorporation ◽  
Stimulatory Action ◽  
Heart Muscle Cells ◽  
Effect Of Glucose ◽  
Stimulation Of

Glucose stimulated the rate of incorporation of [3H]leucine into HCLO4-insoluble fraction of cultured rat heart muscle cells under both aerobic and anaerobic conditions. In the aerobic system the incorporation proceeded at a constant rate during 3h of incubation with and without glucose whereas in the anaeorbic system the incorporation ceased after approx. 60 min and could be renewed only by the addition of glucose. No correlation was found to exist between the above effect of glucose on protein synthesis and glucose-dependent changes in the intracellular ATP concentration. The extent of the stimulation of protein synthesis was related to the concentration of glucose. The effect of glucose was suppressed by cycloheximide but was not affected by actinomycin D. Glucose had no effect on the rate of transport of α-aminoisobutyric acid. Mannose also stimulated [3H]leucine incorporation. Substances that did not produce lactate were ineffective. Iodoacetate inhibited the stimulatory effect of glucose, but pyruvate, which by itself had no apprecialbe stimulatory action, relieved the inhibition induced by iodoacetate. There was no concomitant change in the concentration of ATP when iodoacetate inhibition was reversed by pyruvate. L-Lactate or other intermediates of energy metabolism could not relieve the inhibitory effect of iodoacetate.

Chemical signaling from colonic smooth muscle cells to DRG neurons in culture

1999 ◽  
Vol 276 (3) ◽  
pp. C602-C610 ◽  
Author(s):  
H. S. Ennes ◽  
S. H. Young ◽  
J. A. Goliger ◽  
E. A. Mayer
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Mechanical Stimulation ◽  
Lucifer Yellow ◽  
Muscle Cells ◽  
Distal Colon ◽  
Cell Types ◽  
Target Cells ◽  
Drg Neurons ◽  
Stimulation Of

Transduction mechanisms between target cells within the intestinal wall and peripheral terminals of extrinsic primary afferent neurons are poorly understood. The purpose of this study was to characterize the interactions between smooth muscle cells from the rat distal colon and lumbar dorsal root ganglion (DRG) neurons in coculture. DRG neurons visually appeared to make contact with several myocytes. We show that brief mechanical stimulation of these myocytes resulted in intracellular Ca2+ concentration ([Ca2+]i) transients that propagated into 57% of the contacting neurites. Direct mechanical stimulation of DRG neurites cultured without smooth muscle had no effect. We also show that colonic smooth muscle cells express multiple connexin mRNAs and that these connexins formed functional gap junctions, as evidenced by the intercellular transfer of Lucifer yellow. Furthermore, thapsigargin pretreatment and neuronal heparin injection abolished the increase in neurite [Ca2+]i, indicating that the neuronal Ca2+signal was triggered by inositol 1,4,5-trisphosphate-mediated Ca2+ release from intracellular stores. Our results provide evidence for intercellular chemical communication between DRG neurites and intestinal smooth muscle cells that mediates the exchange of second messenger molecules between different cell types.

scholarly journals Tetrodotoxin Desensitization in Aggregates of Embryonic Chick Heart Cells

1973 ◽  
Vol 62 (3) ◽  
pp. 286-302 ◽  
Author(s):  
Terence F. McDonald ◽  
Howard G. Sachs ◽  
Robert L. DeHaan
Keyword(s):  
Protein Synthesis ◽  
Time Course ◽  
Mean Value ◽  
Slow Inward Current ◽  
Heart Cell ◽  
Heart Cells ◽  
Initial Sensitivity ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
The Mean

Spontaneous beating of heart-cell aggregates from 4-day chick embryos was initially blocked by 10-5 g/ml tetrodotoxin (TTX). With continued exposure to the drug, the fraction of blocked aggregates decreased from about 80% at 15 min to about 25% at 2–3 h, at which time, beating aggregates had become desensitized to the toxin, showing no response to a fresh dose. Aggregates from 5-day hearts were more sensitive to TTX, but fewer became desensitized in its presence. Desensitization to TTX was not seen in 6- and 7-day aggregates. Inhibition of protein synthesis by cycloheximide did not affect beating or initial sensitivity to TTX of 4-day aggregates, but desensitization failed to occur. Before TTX, the mean value of maximal upstroke velocity (Vmax) of the action potentials in 4-day aggregates was 33 V/s. After desensitization Vmax was 12 V/s. Activity of desensitized aggregates in the presence of TTX was augmented by elevated calcium levels, and suppressed by presumed inhibitors of slow inward current (manganese, D600). Desensitization was reversible; upon removal of TTX 10-5 g/ml, aggregates regained their responsiveness to a fresh dose of the drug with a 2–3 h time-course similar to that of desensitization. This was prevented by continued exposure to TTX at concentrations as low as 10-8 g/ml. These data suggest that (a) desensitization involves a change in the mode of action-potential generating from one involving Na-specific, TTX-sensitive channels to one utilizing slower Mn-sensitive channels; (b) the process of desensitization occurs over a period of 2–3 h and is dependent upon the products of protein synthesis; and (c) desensitization is reversible after removal of TTX over a 2–3 h time-course similar to its onset.

scholarly journals Prostaglandin production in myotube cultures. Influence on protein turnover

1988 ◽  
Vol 253 (3) ◽  
pp. 745-749 ◽  
Author(s):  
M A McElligott ◽  
L Y Chaung ◽  
V Baracos ◽  
E A Gulve
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Arachidonic Acid ◽  
Protein Turnover ◽  
Muscle Cells ◽  
Cell Types ◽  
Experimental Conditions ◽  
Adult Skeletal Muscle ◽  
Fetal Bovine ◽  
Pg E2

The production of prostaglandins (PG) E2 and F2 alpha and their possible role in regulation of protein turnover in cultured skeletal-muscle cells were examined. Primary chick myoblasts and myotubes, and L8 myotubes, produced PGE2 and PGF2 alpha from endogenous arachidonic acid. PG production by all three cell types was increased manyfold by the addition of exogenous arachidonic acid. Arachidonate-stimulated PG production was inhibited by the addition of indomethacin (0.1 mM). When L8 and chick myotubes were treated with PGE2, PGF2 alpha, arachidonic acid (0.01 mM) or indomethacin (0.1 mM), no significant alterations in rates of protein synthesis or degradation were observed. Rates of protein synthesis and degradation in these cells were responsive to the addition of 10% fetal-bovine serum under identical experimental conditions. Thus, in contrast with incubated adult skeletal muscle, it appears that the production of prostaglandin metabolites from arachidonic acid is unrelated to regulation of protein turnover in cultured muscle cells.

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