Epinephrine action on glucose uptake by rat diaphragm; effect of ionic composition

1960 ◽  
Vol 199 (2) ◽  
pp. 226-228 ◽  
Author(s):  
Marta Szabo Herman ◽  
Estelle R. Ramey
Keyword(s):  
Glucose Uptake ◽  
Ionic Composition ◽  
Inhibitory Effect ◽  
Ion Concentration ◽  
Rat Diaphragm ◽  
Experimental Conditions ◽  
Glucose Phosphorylation ◽  
Vitro Effect ◽  
Phosphate Medium

The in vitro inhibitory effect of epinephrine on glucose uptake by the isolated rat diaphragm was reinvestigated under various experimental conditions. This effect of epinephrine was manifest only in the Krebs-Ringer phosphate incubating medium and did not occur in the Krebs-Henseleit bicarbonate medium or in the phosphate medium in which the concentration of Mg++ was increased twofold. A change in the concentration of Ca++ ions in the phosphate incubating medium did not affect the inhibition produced by epinephrine. An increase in H+ ion concentration in the phosphate medium diminished control glucose uptake as well as the inhibitory effect of epinephrine. It is suggested that the absence of in vitro inhibition of glucose uptake by epinephrine in the bicarbonate and high Mg phosphate media is due to the normal functioning of the phosphofructokinase enzyme system in these two media only. This in turn produces a faster rate of removal of glucose-6-phosphate, the product of glucose phosphorylation and glycogen breakdown. The accumulation of glucose-6-phosphate would inhibit the enzyme hexokinase, as is the case in the phosphate medium. An explanation for the conflicting reports in the literature regarding the in vitro effect of epinephrine on glucose uptake in muscle is suggested.

pH of isolated resting skeletal muscle and its relation to potassium content

1963 ◽  
Vol 204 (6) ◽  
pp. 1048-1054 ◽  
Author(s):  
Ronald B. Miller ◽  
Ian Tyson ◽  
Arnold S. Relman
Keyword(s):  
Skeletal Muscle ◽  
Intracellular Ph ◽  
Potassium Content ◽  
Ion Concentration ◽  
Detectable Effect ◽  
Rat Diaphragm ◽  
Intracellular Acidosis ◽  
Experimental Conditions ◽  
Hydrogen Ion Concentration

Intracellular pH of isolated rat diaphragm was measured with both a C14-DMO method and a tissue CO2 technique. The values for intracellular pH by each method, although slightly different, changed in parallel under most experimental conditions. Acute, severe potassium depletion in vitro had no detectable effect on intracellular pH, nor did prior depletion in vivo followed by incubation in a potassium-free bath. This was true whether or not the potassium-depleted muscle was exposed to normal or elevated extracellular levels of bicarbonate, and was unaffected by the presence of cationic amino acids in the bath. Acute repletion of previously potassium-depleted muscle resulted in a small rise in cell pH, but this was no greater than that produced by loading normal tissues with potassium. It is concluded that under the conditions of these experiments there is no evidence of intracellular acidosis in potassium-depleted skeletal muscle. Rat diaphragm can lose up to half its potassium content in vitro without detectable increase in hydrogen ion concentration.

In vitro Effect of Growth Hormone on the Glucose Uptake of Isolated Rat Diaphragm

Nature ◽  
1957 ◽  
Vol 179 (4557) ◽  
pp. 472-473 ◽  
Author(s):  
P. J. RANDLE ◽  
J. E. WHITNEY
Keyword(s):  
Growth Hormone ◽  
Glucose Uptake ◽  
Rat Diaphragm ◽  
Vitro Effect ◽  
Isolated Rat

SENSITIVITY OF THE RAT DIAPHRAGM TO GROWTH HORMONE.

1967 ◽  
Vol 54 (4) ◽  
pp. 645-662 ◽  
Author(s):  
Å. Hjalmarson ◽  
K. Ahrén
Keyword(s):  
Growth Hormone ◽  
Inhibitory Effect ◽  
Rat Diaphragm ◽  
Intracellular Accumulation ◽  
Slight Effect ◽  
Kidney Capsule ◽  
Muscle Tissues ◽  
Hypophysectomized Rats ◽  
Isolated Rat

ABSTRACT The effect of growth hormone (GH) in vitro on the rate of intracellular accumulation of the non-utilizable amino acid α-aminoisobutyric acid (AIB) was studied in the intact rat diaphragm preparation. Bovine or ovine GH (25 μg/ml incubation medium) markedly stimulated the accumulation of AIB-14C by diaphragms from hypophysectomized rats, while there was no or only a very slight effect on diaphragms from normal rats. In diaphragms from rats with the pituitary gland autotransplanted to the kidney capsule GH in vitro stimulated the accumulation of AIB-14C significantly more than in diaphragms from normal rats but significantly less than in diaphragms from hypophysectomized rats. Injections of GH intramuscularly for 4 days to hypophysectomized rats made the diaphragms from these rats less sensitive or completely insensitive to GH in vitro. These results indicate strongly that the relative insensitivity to GH in vitro of diaphragms from normal rats is due to the fact that the muscle tissues from these rats has been exposed to the endogenously secreted GH. The results show that GH can influence the accumulation of AIB-14C in the isolated rat diaphragm in two different ways giving an acute or »stimulatory« effect and a late or »inhibitory« effect, and that it seems to be a time-relationship between these two effects of the hormone.

ANALYSIS OF THE BIPHASIC ACTION OF GROWTH HORMONE IN VITRO ON THE RAT DIAPHRAGM

1968 ◽  
Vol 57 (3_Suppl) ◽  
pp. S19-S35 ◽  
Author(s):  
Å. Hjalmarson
Keyword(s):  
Growth Hormone ◽  
Actinomycin D ◽  
Accumulation Rate ◽  
Inhibitory Effect ◽  
Bovine Growth Hormone ◽  
Rat Diaphragm ◽  
Dual Nature ◽  
Hypophysectomized Rats ◽  
D 20

ABSTRACT In vitro addition of bovine growth hormone (GH) to intact hemidiaphragms from hypophysectomized rats has previously been found to produce both an early stimulatory effect lasting for 2—3 hours and a subsequent late inhibitory effect during which the muscle is insensitive to further addition of GH (Hjalmarson 1968). These effects on the accumulation rate of α-aminoisobutyric acid (AIB) and D-xylose have been further studied. In presence of actinomycin D (20 μg/ml) or puromycin (100 μg/ml) the duration of the stimulatory effect of GH (25 μg/ml) was prolonged to last for at least 4—5 hours and the late inhibitory effect was prevented. Similar results were obtained when glucose-free incubation medium was used. Preincubation of the diaphragm at different glucose concentrations (0—5 mg/ml) for 3 hours did not change the GH sensitivity. Addition of insulin at start of incubation could not prevent GH from inducing its late inhibitory effect, while dexamethasone seemed to potentiate this effect of GH. Furthermore, adrenaline was found to decrease the uptake of AIB-14C and D-xylose-14C in the diaphragm, but not to change the sensitivity of the muscle to GH. Preincubation of the diaphragm for 3 hours with puromycin in a concentration of 200 μg/ml markedly decreased the subsequent basal uptake of both AIB-14C and D-xylose-14C, in the presence of puromycin, and abolished the stimulatory effect of GH on the accumulation of AIB-14C. However, the effect of GH on the accumulation of D-xylose-14C was unchanged. The present observations are discussed and evaluated in relation to various mechanisms of GH action proposed to explain the dual nature of the hormone.

scholarly journals Inhibitory effect of sodium metabisulphite and chlorine on growth of Aspergillus spp. and Penicillium spp. strains isolated from marine shrimp

2013 ◽  
Vol 43 (9) ◽  
pp. 1721-1726 ◽  
Author(s):  
Ygor Flávio de Moraes Santos ◽  
Átyla Peeter Batista Veloso ◽  
Rodrigo Maciel Calvet ◽  
Maria Marlúcia Gomes Pereira ◽  
Carina Maricel Pereyra ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Shrimp Farming ◽  
Penicillium Species ◽  
Sodium Metabisulphite ◽  
Marine Shrimp ◽  
Total Fungi ◽  
Frozen Shrimp ◽  
Vitro Effect ◽  
Penicillium Spp

The sodium metabisulphite (SMB) is used in shrimp farming to prevent melanosis and the 5.0 ppm chlorine (CL) concentration used in the shrimp processing is efficient as a bactericide, but there is no evidence of the effectiveness of these chemical compounds as fungicides. Therefore, the aim of this study was to evaluate the in vitro effect of sodium metabisulphite (SMB) and chlorine (CL) on the growth of Aspergillus and Penicillium species isolated from marine shrimp in different stages of processing. The samples were collected from a frozen shrimp processing industry, located in Piauí State, Brazil. The total fungi and occurrence of Aspergillus and Penicillium species were evaluated. For in vitro sensibility test using the diffusion disk in agar method, five concentrations of SMB (0%, 1%, 3%, 5% and 10%) and six of CL (0, 1, 2, 3, 4 and 5 µg mL-1) were used. The fungal counts in the different processing stages ranged from 1.74 to 3.38 CFU g-1. Twenty-nine Aspergillus strains were isolated, prevailing A. versicolor (59.3%) and twenty-two of Penicillium, prevailing P. citrinum (74%). One strain of A. flavus was AFB1 producer. All the isolated strains of P. citrinum produced citrinin. All tested species were in vitro sensitive to 3% of SMB, except the A. flavus. The 10% concentration of SMB inhibited the in vitro growth of all strains. The CL concentrations tested did not inhibit the studied species growth and SMB concentrations above 3.0% inhibited in vitro the growth of the tested strains.

THE INFLUENCE OF POTASSIUM ION UPON GLUCOSE UPTAKE AND GLYCOGEN SYNTHESIS IN THE ISOLATED RAT DIAPHRAGM

1955 ◽  
Vol 33 (1) ◽  
pp. 687-694 ◽  
Author(s):  
D. W. Clarke
Keyword(s):  
Glucose Uptake ◽  
Glycogen Synthesis ◽  
Potassium Ion ◽  
Ion Concentration ◽  
Rat Diaphragm ◽  
High Potassium ◽  
High Concentrations ◽  
Glycogen Breakdown ◽  
Isolated Rat

The amounts of glucose taken from a medium, and the amounts of glycogen synthesized, by rat hemidiaphragms were studied under various conditions. High concentrations of potassium ion inhibited the glucose uptake and there was also a reduced net glycogen synthesis. Glycogen breakdown was probably not increased by high potassium ion concentration. The effect of potassium was most marked when conditions were such that one would ordinarily expect a considerable glucose uptake or glycogen synthesis. The action of insulin was not peculiarly susceptible to potassium ion inhibition.

scholarly journals Angiotensin II inhibits NaCl absorption in the rat medullary thick ascending limb

2004 ◽  
Vol 287 (3) ◽  
pp. F404-F410 ◽  
Author(s):  
Nicolas Lerolle ◽  
Soline Bourgeois ◽  
Françoise Leviel ◽  
Gaëtan Lebrun ◽  
Michel Paillard ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Plasma Membranes ◽  
Inhibitory Effect ◽  
Thick Ascending Limb ◽  
Sprague Dawley ◽  
Experimental Conditions ◽  
Nacl Absorption ◽  
Medullary Thick Ascending Limb

NaCl reabsorption in the medullary thick ascending limb of Henle (MTALH) contributes to NaCl balance and is also responsible for the creation of medullary interstitial hypertonicity. Despite the presence of angiotensin II subtype 1 (AT1) receptors in both the luminal and the basolateral plasma membranes of MTALH cells, no information is available on the effect of angiotensin II on NaCl reabsorption in MTALH and, furthermore, on angiotensin II-dependent medullary interstitial osmolality. MTALHs from male Sprague-Dawley rats were isolated and microperfused in vitro; transepithelial net chloride absorption ( JCl) as well as transepithelial voltage ( Vte) were measured. Luminal or peritubular 10−11 and 10−10 M angiotensin II had no effect on JCl or Vte. However, 10−8 M luminal or peritubular angiotensin II reversibly decreased both JCl and Vte. The effect of both luminal and peritubular angiotensin II was prevented by the presence of losartan (10−6 M). By contrast, PD-23319, an AT2-receptor antagonist, did not alter the inhibitory effect of 10−8 M angiotensin II. Finally, no additive effect of luminal and peritubular angiotensin II was observed. We conclude that both luminal and peritubular angiotensin II inhibit NaCl absorption in the MTALH via AT1 receptors. Because of intrarenal angiotensin II synthesis, angiotensin II concentration in medullary tubular and interstitial fluids may be similar in vivo to the concentration that displays an inhibitory effect on NaCl reabsorption under the present experimental conditions.

scholarly journals In Vitro Effect of Local Anesthetics onCandida albicansGerm Tube Formation

1994 ◽  
Vol 1 (4) ◽  
pp. 193-197 ◽  
Author(s):  
Acácio Rodrigues ◽  
Cidália Pina Vaz ◽  
A. Freitas Fonseca ◽  
J. Martinez de Oliveira ◽  
Henrique Barros
Keyword(s):  
Germ Tube ◽  
Inhibitory Effect ◽  
Tube Formation ◽  
Vaginal Candidiasis ◽  
Sabouraud Agar ◽  
Colony Forming Units ◽  
Vitro Effect ◽  
Phosphate Buffered Saline ◽  
Dose Dependent

Objective:This study was planned to clarify the in vitro effect of lidocaine and bupivacaine on germ tube formation byCandida albicansisolates from cases of clinical vaginal candidiasis.Methods:FourteenC. albicansstrains (clinical vaginal isolates) were grown on Sabouraud agar for 24 h at 37℃ and tested as follows: 100 μl of a yeast suspension [105colony forming units (CFU)/ml of phosphate buffered saline (PBS)] was added to 500 μl of fresh human serum with lidocaine or bupivacaine (pure salts) in serial concentrations. The test was run in duplicate. Controls were prepared for each strain. After 4 h of incubation at 37℃, samples were taken from each vial and 200 yeasts were counted in a counting chamber. The pH of each suspension was measured.Results:The results are given as the mean of the 2 readings and are expressed as the percentage of blastoconidia with germ tubes/total blastoconidia.Conclusions:Our experiments show that both lidocaine and bupivacaine have a dose-dependent inhibitory effect, pH-independent, on germ tube formation byC. albicansand that both drugs seem to be promising in the treatment of genital candidiasis due to the combination of anesthetic and antifungal properties.

A novel mechanism of olanzapine-induced lipid accumulation

2011 ◽  
Vol 26 (S2) ◽  
pp. 906-906 ◽  
Author(s):  
S. Dzitoyeva ◽  
H. Chen ◽  
R. Manev ◽  
H. Manev
Keyword(s):  
Lipid Content ◽  
Direct Action ◽  
Inhibitory Effect ◽  
Experimental Conditions ◽  
Cell Content ◽  
Metabolic Alterations ◽  
Low Concentrations ◽  
Mrna Content ◽  
Quantitative Western Blot

IntroductionSecond generation antipsychotic drugs (SGADs) including olanzapine trigger adverse metabolic alterations possibly by a direct action on adipocytes.Objectives and aimsThe system of the inflammatory 5-lipoxygenase (5-LOX) and its activating protein (FLAP) have been implicated in lipid dysfunction in obesity. We investigated whether this system could participate in the adipogenic action of olanzapine.MethodsExperiments were performed in 3T3-L1 adipocytes in vitro. Cells were treated with olanzapine and a FLAP inhibitor MK-886. Their lipid content, 5-LOX and FLAP mRNA content, and FLAP protein content were measured.ResultsOlanzapine treatment did not affect the cell content of 5-LOX mRNA; however, it decreased FLAP mRNA content at day five but not 24 hours after olanzapine addition. The inhibitory effect of olanzapine on FLAP expression was confirmed by quantitative Western blot assays. In the absence of a FLAP inhibitor, low concentrations of olanzapine (0.5 and 5 μM) increased lipid content only by about 13% (compared to about a 56% increase induced by 50 μM olanzapine) whereas in the presence of MK-886 these concentrations of olanzapine produced lipid increases comparable to the increase caused by 50 μM. In these experimental conditions, MK-886 alone did not alter the cell content of lipids.Conclusions5-LOX system may be involved in lipid dysfunction not only in conditions of obesity but possibly in SGAD-related metabolic alterations. The known polymorphism in the genes of the human 5-LOX system could play a role in setting a variable individual susceptibility to the metabolic side effects of SGADs.

THE EFFECT OF GROWTH HORMONE AND OF CORTISOL ON THE RESPONSE OF ISOLATED RAT DIAPHRAGM TO THE STIMULATING EFFECT OF INSULIN ON GLUCOSE UPTAKE AND ON INCORPORATION OF AMINO ACIDS INTO PROTEIN

1959 ◽  
Vol 18 (4) ◽  
pp. 395-408 ◽  
Author(s):  
K. L. MANCHESTER ◽  
P. J. RANDLE ◽  
F. G. YOUNG
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Glucose Uptake ◽  
Carbohydrate Metabolism ◽  
Rat Diaphragm ◽  
Pituitary Growth Hormone ◽  
Isolated Rat ◽  
Stimulation Of

SUMMARY 1. The effect of hypophysectomy, or of adrenalectomy, and injection of pituitary growth hormone (GH) or of cortisol, on the uptake of glucose and the incorporation of glycine into protein by isolated rat diaphragm, and the effect of the addition of insulin in vitro on these processes, has been studied. 2. Both hypophysectomy and adrenalectomy raised the uptake of glucose by isolated diaphragm, while treatment of the intact or of the hypophysectomized rat with GH, or of the intact or of the adrenalectomized rat with cortisol, depressed it. Although hypophysectomy and adrenalectomy did not influence the additional glucose uptake induced by 200 mu./ml. of insulin in vitro, both these operations enhanced the effect of 0·1–1·0 mu./ml. of insulin on glucose uptake by diaphragm in vitro. Treatment of the rat with GH or cortisol diminished the rise in glucose uptake of diaphragm induced by 0·1–1·0 mu./ml. insulin. 3. Hypophysectomy depressed, and administration of GH to the intact or hypophysectomized rat raised, the incorporation of glycine into protein of the isolated diaphragm, but neither of these operations altered the magnitude of the stimulation of incorporation induced by 1·0 mu./ml. insulin. 4. Adrenalectomy raised, and administration of cortisol to the intact or adrenalectomized rat depressed, the incorporation of glycine into protein of the isolated diaphragm; adrenalectomy enhanced, the injection of cortisol diminished, the effect of 1·0 mu./ml. insulin on these processes. 5. The possibility that GH directs insulin towards the stimulation of protein synthesis, in part by restraining the action of insulin on carbohydrate metabolism, is discussed.

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