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

1955 ◽  
Vol 33 (4) ◽  
pp. 687-694 ◽  
Author(s):  
D. W. Clarke

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.

1955 ◽  
Vol 33 (1) ◽  
pp. 687-694 ◽  
Author(s):  
D. W. Clarke

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.


1960 ◽  
Vol 198 (5) ◽  
pp. 1075-1078 ◽  
Author(s):  
E. R. Berman ◽  
E. Wertheimer

A factor has been found in the serum of fasted rats which inhibits glucose uptake and glycogen synthesis in the isolated rat diaphragm. It does not affect CO2 production or O2 uptake. It is nondialyzable, stable in the cold and also stable when heated to 58°C for 1 hour. It was found in Cohn fraction IV-V. Its action did not resemble any of the known hormones, nor could it be identified as one of the inhibitory factors found in diabetic serum.


1955 ◽  
Vol 33 (5) ◽  
pp. 845-848
Author(s):  
D. W. Clarke

The effects of adrenal cortical extract upon glucose uptake and upon glycogen synthesis in the isolated rat diaphragm were studied in three different media. The maximum inhibition by the extract upon the measured effects was seen in a medium which contained both sodium and potassium ions. In media which contained either of these alone as the major cation, there was no significant inhibition.


1955 ◽  
Vol 33 (1) ◽  
pp. 845-848
Author(s):  
D. W. Clarke

The effects of adrenal cortical extract upon glucose uptake and upon glycogen synthesis in the isolated rat diaphragm were studied in three different media. The maximum inhibition by the extract upon the measured effects was seen in a medium which contained both sodium and potassium ions. In media which contained either of these alone as the major cation, there was no significant inhibition.


1961 ◽  
Vol 23 (2) ◽  
pp. 193-207 ◽  
Author(s):  
A. K. HUGGINS ◽  
J. H. OTTAWAY

SUMMARY A peptide has been isolated from crystalline ox growth hormone (GH) which stimulates glucose uptake by isolated rat diaphragm when incubated with it at low concentrations (0·01 μg./ml. medium). The peptide also causes a slight but persistent hypoglycaemia in fasted mice and rabbits. The increase in glucose uptake by diaphragm is not accompanied by increased glycogen synthesis; in certain circumstances it causes a diminution in lactate output. When incubated with normal rat diaphragm in the absence of acetate, very high concentrations (10 μg./ml.) cause an inhibition of glucose uptake. The peptide appears to have negligible effects on fat metabolism. The peptide has a mol. wt. of 5,000–10,000, an isoelectric point of about pH 6, and an N-terminal methionine. The amino acid composition is noteworthy for the complete absence of basic amino acids. It is concluded that ox GH freed from this peptide will stimulate glycogen synthesis by muscle without increasing the uptake of glucose.


1952 ◽  
Vol 197 (1) ◽  
pp. 151-166 ◽  
Author(s):  
C.R. Park ◽  
David H. Brown ◽  
Marvin. Cornblath ◽  
William H. Daughaday ◽  
M.E. Krahl

1965 ◽  
Vol 48 (5) ◽  
pp. 859-872 ◽  
Author(s):  
Clay M. Armstrong ◽  
Leonard Binstock

The injection of tetraethylammonium chloride into the giant axon of the squid prolongs the action potential and eliminates most of the late current under voltage-clamp. Experiments on fibers in an external medium of high potassium ion concentration demonstrate that injected tetraethylammonium chloride causes rectification of the instantaneous current-voltage curve for potassium by excluding outward current. This interference with the flow of outward potassium ion current underlies the prolongation of the action potential seen in tetraethylammonium-injected fibers.


Nature ◽  
1957 ◽  
Vol 179 (4557) ◽  
pp. 472-473 ◽  
Author(s):  
P. J. RANDLE ◽  
J. E. WHITNEY

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