Inhibitory Effect of Glucose on Enzyme Formation

Nature ◽  
1956 ◽  
Vol 178 (4537) ◽  
pp. 801-802 ◽  
Author(s):  
FREDERICK C. NEIDHARDT ◽  
BORIS MAGASANIK
Keyword(s):  
Inhibitory Effect ◽  
Enzyme Formation ◽  
Effect Of Glucose

scholarly journals Effect of glucose on carbohydrate synthesis from alanine or lactate in hepatocytes from starved rats

1980 ◽  
Vol 192 (1) ◽  
pp. 377-380 ◽  
Author(s):  
K Solanki ◽  
F Nyfeler ◽  
U K Moser ◽  
P Walter
Keyword(s):  
Inhibitory Effect ◽  
Label Free ◽  
Carbohydrate Synthesis ◽  
No Inhibition ◽  
Effect Of Glucose ◽  
Substrate Addition

In hepatocytes from starved rats, 10mM-glucose suppressed in incorporation of 2mM labelled alanine into glucose+glycogen by more than 40%, whereas no inhibition was observed with labelled lactate as substrate. Addition of glycerol instead of glucose did not show this inhibition. The inhibitory effect could also be demonstrated in label-free experiments.

PROTEINASE BIOSYNTHESIS BY STREPTOCOCCUS LIQUEFACIENS: II. PURINE, PYRIMIDINE, AND VITAMIN REQUIREMENTS

1957 ◽  
Vol 3 (4) ◽  
pp. 553-558 ◽  
Author(s):  
R. E. Hartman ◽  
L. N. Zimmerman ◽  
R. Rabin
Keyword(s):  
Synthetic Medium ◽  
Inhibitory Effect ◽  
Enzyme Synthesis ◽  
Nitrogen Bases ◽  
Best Response ◽  
Straight Line ◽  
Amino Acid Requirements ◽  
Enzyme Formation ◽  
Vitamin Requirements ◽  
Initial Medium

Proteinase biosynthesis by Streptococcus liquefaciens, strain 31, may be obtained from an entirely synthetic medium. Adenine and uracil seem to satisfy best the purine and pyrimidine requirement while pyridoxal and riboflavin is the combination of vitamins that leads to maximal enzyme biosynthesis. Biotin and folic acid together, or thiamine, have an inhibitory effect on enzyme synthesis. The amino acid requirements for optimum activity are unaffected by the reduced number of vitamins and nitrogen bases present in the final medium as compared to the initial medium. A reduction in the number of vitamins (to pyridoxal and riboflavin), however, showed that only adenine and uracil gave the best response to the purine and pyrimidine demands for biosynthesis; prior to this, in the presence of a complete vitamin pool, several combinations of nitrogen bases yielded equal enzymatic activity. When proteinase synthesis is plotted against time, enzyme formation ceases at about 3 hours. The shape of the curve indicates a straight-line relationship after an initial lag period of 90 minutes.

Activation of members of the mitogen-activated protein kinase family by glucose in endothelial cells

2000 ◽  
Vol 279 (4) ◽  
pp. E782-E790 ◽  
Author(s):  
Wenli Liu ◽  
Aaron Schoenkerman ◽  
William L. Lowe
Keyword(s):  
Endothelial Cells ◽  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Normal Growth ◽  
Inhibitory Effect ◽  
Mitogen Activated Protein Kinase ◽  
P38 Kinase ◽  
Hexosamine Pathway ◽  
Mitogen Activated Protein ◽  
Effect Of Glucose

To better understand the molecular mechanisms for hyperglycemia-induced proatherogenic changes in endothelial cells, the effect of high glucose on activation of members of the mitogen-activated protein kinase (MAPK) family, including c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK)-1, -2, and -5, and p38 kinase, was examined in bovine pulmonary artery endothelial cells (PAEC). Glucose, fructose, and raffinose induced a concentration-dependent decrease in PAEC growth. Addition of 25 mM glucose, fructose, or raffinose to normal growth medium stimulated an approximately twofold increase in JNK1 activity that was maximal after 24 h, whereas only glucose markedly increased ERK5 activity. Neither ERK1/2 nor p38 kinase activity was increased by glucose, fructose, or raffinose. The antioxidant N-acetylcysteine partially abrogated the glucose-induced increase in ERK5 activity but had no effect on the increase in JNK1 activity. In contrast, azaserine, which prevents increased flux through the hexosamine pathway, decreased glucose-induced JNK1 activity but had no effect on fructose- or raffinose-induced JNK1 activity. Consistent with this finding, glucosamine stimulated a 2.4-fold increase in JNK1 activity and reproduced the inhibitory effect of glucose on PAEC growth. In summary, glucose activates different members of the MAPK family in PAEC via distinct mechanisms. Moreover, the correlation between the ability of different sugars to activate JNK1 and inhibit cell growth suggests that activation of this signaling pathway may contribute to the growth inhibitory effect of glucose in endothelial cells.

scholarly journals Inorganic Phosphate Induces Spore Morphogenesis and Enterotoxin Production in the Intestinal Pathogen Clostridium perfringens

2006 ◽  
Vol 74 (6) ◽  
pp. 3651-3656 ◽  
Author(s):  
Valeria A. Philippe ◽  
Marcelo B. Méndez ◽  
I-Hsiu Huang ◽  
Lelia M. Orsaria ◽  
Mahfuzur R. Sarker ◽  
...  
Keyword(s):  
Clostridium Perfringens ◽  
Inorganic Phosphate ◽  
Food Poisoning ◽  
Inhibitory Effect ◽  
Physiological Signal ◽  
Food Borne ◽  
Intestinal Pathogen ◽  
Important Virulence Factor ◽  
Dna Partitioning ◽  
Effect Of Glucose

ABSTRACT Clostridium perfringens enterotoxin (CPE) is an important virulence factor for food poisoning and non-food borne gastrointestinal (GI) diseases. Although CPE production is strongly regulated by sporulation, the nature of the signal(s) triggering sporulation remains unknown. Here, we demonstrated that inorganic phosphate (Pi), and not pH, constitutes an environmental signal inducing sporulation and CPE synthesis. In the absence of Pi-supplementation, C. perfringens displayed a spo0A phenotype, i.e., absence of polar septation and DNA partitioning in cells that reached the stationary phase of growth. These results received support from our Northern blot analyses which demonstrated that Pi was able to counteract the inhibitory effect of glucose at the onset of sporulation and induced spo0A expression, indicating that Pi acts as a key signal triggering spore morphogenesis. In addition to being the first study reporting the nature of a physiological signal triggering sporulation in clostridia, these findings have relevance for the development of antisporulation drugs to prevent or treat CPE-mediated GI diseases in humans.

Nutrient feedback inhibition of gastric emptying plays a larger role than osmotically dependent duodenal resistance

1993 ◽  
Vol 265 (4) ◽  
pp. G672-G676
Author(s):  
H. C. Lin ◽  
J. D. Elashoff ◽  
Y. G. Gu ◽  
J. H. Meyer
Keyword(s):  
Gastric Emptying ◽  
Analysis Of Variance ◽  
Feedback Inhibition ◽  
Inhibitory Effect ◽  
Duodenal Fistula ◽  
Inhibitory Feedback ◽  
Specific Feedback ◽  
Hyperosmolar Solutions ◽  
Effect Of Glucose ◽  
Hyperosmolar Glucose

The slowing of gastric emptying by hyperosmolar solutions has been postulated to result from the triggering of duodenal osmoreceptor feedback on the stomach. We tested the idea that the inhibition of gastric emptying by a hyperosmolar solution depended on the duodenal resistance and the triggering of nutrient-specific feedback by tracking gastric emptying of 300 and 1,200 mosmol/kgH2O test solutions in 12 dogs in which duodenal resistance was either removed (by temporarily diverting chyme from uncorked duodenal fistula) or preserved (by keeping duodenal fistula corked). Mannitol was used to test osmolality alone, and glucose was used to examine the combined effects of osmolality and nutrient-specific inhibitory feedback. We found that: 1) the slowing effect of hyperosmolality was more marked with the duodenal resistance preserved (P < 0.05; analysis of variance), 2) the slowing effect of glucose was greater than that of mannitol for all conditions (P = 0.01; analysis of variance), and 3) the inhibitory effect of mannitol was localized to the duodenum. We conclude that inhibition of gastric emptying by hyperosmolar mannitol depended primarily on duodenal resistance, while the inhibitory effect of hyperosmolar glucose depended on nutrient-specific feedback on the stomach more than duodenal resistance.

Exogenous substrate utilization by isolated myocytes from chronically diabetic rats

1983 ◽  
Vol 245 (1) ◽  
pp. C46-C51 ◽  
Author(s):  
V. Chen ◽  
G. J. Bagby ◽  
J. J. Spitzer
Keyword(s):  
Inhibitory Effect ◽  
Diabetic Rats ◽  
Lactate Oxidation ◽  
Palmitate Oxidation ◽  
Exogenous Substrate ◽  
Streptozotocin Induced Diabetes ◽  
And Control ◽  
Effect Of Glucose ◽  
Substrate Concentrations

The effect of chronic streptozotocin-induced diabetes on the utilization of exogenous substrates by freshly isolated, Ca2+-tolerant nonbeating myocytes was investigated. The rates of glucose (5 or 25 mM) and lactate (1 mM) oxidation were significantly reduced in myocytes of diabetic rats, whereas palmitate (0.4 or 1 mM) oxidation was similar to the controls. Glucose oxidation in diabetic (but not in control) and palmitate oxidation in control (but not in diabetic) myocytes were increased by raising the respective substrate concentrations in the medium to levels found in vivo in diabetic rats. Inhibition of glucose and lactate oxidation in the presence of competing substrates were generally similar between control and diabetic myocytes. However, the inhibitory effect of glucose on lactate oxidation was greater in control cells. The rate of palmitate oxidation was diminished by glucose in the controls, but this was not observed in the diabetic myocytes. Oxygen consumption by the myocytes of diabetic rats was below that of control cells when lactate or palmitate was present in the medium. ATP and phosphocreatine contents were similar in the myocytes of diabetic and control rats. All the observed changes in myocytes prepared from diabetic rats were reversed by in vivo insulin treatment.

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