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Proteolytic and lipolytic responses to starvation.
- Source :
-
Nutrition (Burbank, Los Angeles County, Calif.) [Nutrition] 2006 Jul-Aug; Vol. 22 (7-8), pp. 830-44. - Publication Year :
- 2006
-
Abstract
- Mammals survive starvation by activating proteolysis and lipolysis in many different tissues. These responses are triggered, at least in part, by changing hormonal and neural statuses during starvation. Pathways of proteolysis that are activated during starvation are surprisingly diverse, depending on tissue type and duration of starvation. The ubiquitin-proteasome system is primarily responsible for increased skeletal muscle protein breakdown during starvation. However, in most other tissues, lysosomal pathways of proteolysis are stimulated during fasting. Short-term starvation activates macroautophagy, whereas long-term starvation activates chaperone-mediated autophagy. Lipolysis also increases in response to starvation, and the breakdown of triacylglycerols provides free fatty acids to be used as an energy source by skeletal muscle and other tissues. In addition, glycerol released from triacylglycerols can be converted to glucose by hepatic gluconeogenesis. During long-term starvation, oxidation of free fatty acids by the liver leads to the production of ketone bodies that can be used for energy by skeletal muscle and brain. Tissues that cannot use ketone bodies for energy respond to these small molecules by activating chaperone-mediated autophagy. This is one form of interaction between proteolytic and lipolytic responses to starvation.
- Subjects :
- Acyl Coenzyme A metabolism
Autophagy
Enzyme Activation
Fatty Acids, Nonesterified metabolism
Humans
Ketone Bodies metabolism
Lysosomes metabolism
Molecular Chaperones physiology
Muscle Proteins metabolism
Muscle, Skeletal chemistry
Proteasome Endopeptidase Complex metabolism
Triglycerides metabolism
Ubiquitin metabolism
Lipolysis
Peptide Hydrolases metabolism
Starvation metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0899-9007
- Volume :
- 22
- Issue :
- 7-8
- Database :
- MEDLINE
- Journal :
- Nutrition (Burbank, Los Angeles County, Calif.)
- Publication Type :
- Academic Journal
- Accession number :
- 16815497
- Full Text :
- https://doi.org/10.1016/j.nut.2006.04.008