Stimulation of glucagon of in vivo phosphorylation of rat hepatic pyruvate kinase.

Riou JP, Claus TH, Pilkis SJ

The Journal of biological chemistry1 Feb 1978Cited by 87 (Europe PMC)

PMID621197DOI10.1016/s0021-9258(17)38152-8PepBankPUB-00621197

Publisher page PubMedAsk about this study

Summary

Rat hepatic pyruvate kinase (type L) has been purified to homogeneity by a simple, rapid procedure involving DEAE-cellulose chromatography and elution from a blue Sepharose column. The enzyme was homogeneous by the criteria of sodium dodecyl sulfate disc gel electrophoresis, had a subunit molecular weight of 57,000, and a specific activity of 558 units/mg of protein at 30 degrees. In order to test whether the enzyme is phosphorylated in vivo, rats were injected with radioactive inorganic phosphate. Incorporation into pyruvate kinase was determined after purification of the enzyme to homogeneity as well as after specific immunoprecipitation of the enzyme from partially purified preparations. Sodium dodecyl sulfate disc gel electrophoresis revealed that 32P was incorporated into the enzyme in both cases. Glucagon administration in vivo resulted in a 200 to 300% increase in the incorporation of 32P into the enzyme which was correlated with an inhibition of enzyme activity and an elevation of hepatic levels of cyclic AMP. These results represent the first demonstration of in vivo phosphorylation of a hepatic glycolytic enzyme and strongly support the hypothesis that glucagon regulates pyruvate kinase activity, at least in part, by a phosphorylation mechanism.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study3

3 results from studies that gave the peptide. No result from this study comes from people.

01AnimalAnimal study (in vivo)Mechanism
In rats, glucagon administration increased phosphate incorporation into hepatic pyruvate kinase by 200 to 300%.
In plain wordsIn rats, glucagon increased phosphate incorporation into liver pyruvate kinase.
Peptide
Glucagon
Outcome
IncreasePyruvate kinase phosphorylation
Study
ratn: not reported in source
Rat liver after in vivo glucagon administration
Outcome group
Receptor activity and mechanism · Liver
Studied dose
Dose not stated
Measurements
Increase in phosphate incorporation
200 to 300%
hepatic pyruvate kinase
Source sentences
Summary
Glucagon administration in vivo resulted in a 200 to 300% increase in the incorporation of 32P into the enzyme which was correlated with an inhibition of enzyme activity and an elevation of hepatic levels of cyclic AMP.
2 context sentences(design, population, supporting numbers)
Summary · context
In order to test whether the enzyme is phosphorylated in vivo, rats were injected with radioactive inorganic phosphate.
Summary · context
Incorporation into pyruvate kinase was determined after purification of the enzyme to homogeneity as well as after specific immunoprecipitation of the enzyme from partially purified preparations.
Show in the study text Report a problemFND-0062119701
02AnimalAnimal study (in vivo)Mechanism
In rats, increased hepatic pyruvate kinase phosphorylation after glucagon correlated with inhibition of enzyme activity.
In plain wordsIn rats, glucagon-associated phosphorylation of liver pyruvate kinase correlated with lower enzyme activity.
Peptide
Glucagon
Outcome
DecreasePyruvate kinase activity
Study
ratn: not reported in source
Rat liver after in vivo glucagon administration
Outcome group
Receptor activity and mechanism · Liver
Studied dose
Dose not stated
Source sentences
Summary
Glucagon administration in vivo resulted in a 200 to 300% increase in the incorporation of 32P into the enzyme which was correlated with an inhibition of enzyme activity and an elevation of hepatic levels of cyclic AMP.
2 context sentences(design, population, supporting numbers)
Summary · context
In order to test whether the enzyme is phosphorylated in vivo, rats were injected with radioactive inorganic phosphate.
Summary · context
Incorporation into pyruvate kinase was determined after purification of the enzyme to homogeneity as well as after specific immunoprecipitation of the enzyme from partially purified preparations.
Show in the study text Report a problemFND-0062119702
03AnimalAnimal study (in vivo)Mechanism
In rats, increased hepatic pyruvate kinase phosphorylation after glucagon correlated with elevated hepatic cyclic AMP.
In plain wordsIn rats, glucagon-associated phosphorylation of liver pyruvate kinase correlated with higher liver cyclic AMP.
Peptide
Glucagon
Outcome
IncreaseHepatic cyclic AMP
Study
ratn: not reported in source
Rat liver after in vivo glucagon administration
Outcome group
Receptor activity and mechanism · Liver
Studied dose
Dose not stated
Source sentences
Summary
Glucagon administration in vivo resulted in a 200 to 300% increase in the incorporation of 32P into the enzyme which was correlated with an inhibition of enzyme activity and an elevation of hepatic levels of cyclic AMP.
2 context sentences(design, population, supporting numbers)
Summary · context
In order to test whether the enzyme is phosphorylated in vivo, rats were injected with radioactive inorganic phosphate.
Summary · context
Incorporation into pyruvate kinase was determined after purification of the enzyme to homogeneity as well as after specific immunoprecipitation of the enzyme from partially purified preparations.
Show in the study text Report a problemFND-0062119703

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
28 Oct 2026, 02:03 UTC
Study results updated
Version 1
27 Oct 2026, 16:35 UTC
First added · source update from Europe PMC

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