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Starvation Increases the Amount of Pyruvate Dehydrogenase Kinase in Several Mammalian Tissues
- Source :
- Archives of Biochemistry and Biophysics. 381:1-7
- Publication Year :
- 2000
- Publisher :
- Elsevier BV, 2000.
-
Abstract
- Covalent modification of the pyruvate dehydrogenase complex provides an important regulatory mechanism for controlling the disposal of glucose and other compounds metabolized to pyruvate. Regulation of the complex by this mechanism is achieved in part by tissue-specific expression of the genes encoding isoenzymes of pyruvate dehydrogenase kinase (PDK). Starvation is known from our previous work to increase PDK activity of heart and skeletal muscle by increasing the amount of PDK isoenzyme 4 (PDK4) present in these tissues. This study demonstrates that increased expression of both PDK4 and PDK2 occurs in rat liver, kidney, and lactating mammary gland in response to starvation. PDK4 and PDK2 message levels were also increased by starvation in the two tissues examined (liver and kidney), suggesting enhancement of gene transcription. Changes in PDK2 message and protein were of similar magnitude, but changes in PDK4 message were greater than those in PDK4 protein, suggesting regulation at the level of translation. In contrast to these tissues, starvation had little or no effect on PDK2 and PDK4 protein in brain, white adipose tissue, and brown adipose tissue. Nevertheless, PDK4 message levels were significantly increased in brain and white adipose tissue by starvation. The findings of this study indicate that increased expression of PDK isoenzymes is an important mechanism for bringing about inactivation of the pyruvate dehydrogenase complex during starvation in many but not all tissues of the body. The absence of this mechanism preserves the capacity of neuronal tissue to utilize glucose for energy during starvation.
- Subjects :
- Male
Pyruvate dehydrogenase kinase
Biophysics
PDK4
Adipose tissue
Mitochondria, Liver
White adipose tissue
Protein Serine-Threonine Kinases
Pyruvate dehydrogenase phosphatase
Biology
Kidney
Biochemistry
Gene Expression Regulation, Enzymologic
Mammary Glands, Animal
Pregnancy
Brown adipose tissue
medicine
Animals
Tissue Distribution
RNA, Messenger
Rats, Wistar
Molecular Biology
Starvation
Brain
Pyruvate Dehydrogenase Acetyl-Transferring Kinase
Pyruvate dehydrogenase complex
Rats
Isoenzymes
Glucose
medicine.anatomical_structure
Female
medicine.symptom
Protein Kinases
Subjects
Details
- ISSN :
- 00039861
- Volume :
- 381
- Database :
- OpenAIRE
- Journal :
- Archives of Biochemistry and Biophysics
- Accession number :
- edsair.doi.dedup.....b8496f23a2d8dc9e51ead9c3379e0de7