Metabolism of Nutrients in Muscle and Adipose Tissue

Anusorn Cherdthong, PhD137748 Applied Biochemistry in Nutritional Science

Email: [email protected]: http://ags.kku.ac.th/eLearning/137748

Metabolism of Nutrients in Muscle and Adipose Tissue

IntroductionProtein and lipid are more

importance role in muscle and tissue

Storage and excretion when required

Some metabolism are similar to liver metabolism

Muscle cell---protein storageAdipose tissue---triacylglyceride

storage

Riis (1983)Metabolism in muscle cell

Metabolism pathway

In muscle cellProtein synthesisProtein lysis

In adipose tissueTriacylglyceride degradationTriacylglyceride storageLipogenesisControl of fatty acid synthesis

Protein synthesis

Transcription: messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA) and small nuclear RNA (snRNA)

InitiationElongationTermination

TranslationInitiationElongationTermination

McDonald et al. (2011)

Protein synthesis in

muscle

McDonald et al. (2011)

tRNA molecule

McDonald et al. (2011)

RNA Translation

Protein lysis

Required proteinasesLower rate than liver—low proteinases proteinases enzymes

cathepsin D alkaline proteinases: Ca2+-activated proteinase or –factor (CAF)

Low protein lysislow protein synthesisStress---high protein lysis

Lipid metabolism

Occurred at adipocyte of adipose tissueControl—triacylglyceride, free FAProvide various substances--- adipokineInduce by hungry, diets, digestion/absorption system, hormone, CNS etc

Riis (2983)

Metabolism in adipose

tissue

Triacylglyceride degradation

Control by hormone systemEnd products are FA and glycerolFA—oxidation---energy (95%)5% energy from glycerol

Nelson and Cox (2000)

Triacylglyceride degradation

Nelson and Cox (2000)

Triacylglyceride degradation control

Triacylglyceride storage

Increase after feedingLDL synthesis at adipose—induce by insulin

glycolytic enzyme phosphofructokinase-1---.>fructose 2,6-bisphosphate

Fatty acyl CoA + glycerol-3-phosphate-triacylglycerol

Insulin induce glucose -FA

Lipogenesis

In ruminant occurred 92% in adipose tissue

Substrate: C2 and C4Energy from NADPH, ATP NADPH—isocitrate and oxaloacetate

In non ruminant occurred in liverSubstrate: glucoseNADPH---pentose shunt --malate dehydrogenase

Van Soest (1982)

FA syvthesis in adipose tissue of ruminant

Control of fatty acid synthesis

Hormone controlledInsulin: induce FA synthesis

Transfer glucose into cellActivated pyruvate dehydrogenase

Enzyme:acetyl-CoA carboxylase acitvate by citrate

NADPH

Conclusion

1

2

Protein and lipid are major metabolism

Muscle storage protein while adipose was storage tryacylglyceride

3 Protein metabolism: RNA transcription, translation

4 Triacylglycerols metabolism was differ among specie animals

Thank you!