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7: Integration of Macronutrient Metabolism

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    Understanding the different metabolic pathways is an important step. However, an integrated understanding of the interconnectedness and tissue specificity of metabolism is where this knowledge really becomes powerful. To this end, you will first learn how the different pathways integrate with one another and then talk about the metabolic capabilities of the different tissues in the body. We will then discuss what happens metabolically during different conditions or when consuming certain diets.

    • 7.1: Integration of Macronutrient Metabolism and Alcohol Metabolic Pathways
      This page explores the integration of macronutrient and alcohol metabolic pathways, featuring a color-coded schematic for carbohydrates, fats, and proteins. It omits glycerol and cholesterol pathways to streamline interactions. Acetyl-CoA is highlighted as a crucial metabolite connecting various pathways, especially in carbohydrate to fat breakdown.
    • 7.2: Liver Macronutrient and Alcohol Metabolism
      This page explains the liver’s crucial role in macronutrient metabolism, detailing its functions such as glycogen synthesis, glycolysis, gluconeogenesis, alcohol oxidation, ketone body synthesis, urea synthesis, and VLDL synthesis. It highlights that the liver is primarily responsible for gluconeogenesis, generating about 90% of glucose, while noting that muscles cannot release glucose due to the absence of glucose-6-phosphatase.
    • 7.3: Extrahepatic Macronutrient Metabolism
      This page examines extrahepatic tissue metabolism, highlighting the liver's role and defining extrahepatic functions. It discusses key metabolic pathways outside the liver, including gluconeogenesis and urea synthesis. The metabolism of four tissues—muscle, adipose, brain, and red blood cells—is detailed: muscle stores glycogen, adipose synthesizes triglycerides, brain uses glucose and ketones, and red blood cells rely solely on glycolysis.
    • 7.4: Metabolic Conditions
      This page examines metabolic processes under various dietary conditions including the fed state, fasting, and specific diets like Atkins and Ornish/Pritikin. It describes the role of insulin and glucagon in glucose and fat metabolism, detailing how glucose is stored as glycogen and fats in the fed state and how the body shifts to burning fat and producing ketone bodies during fasting and low-carb diets.

    This page titled 7: Integration of Macronutrient Metabolism is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Brian Lindshield via source content that was edited to the style and standards of the LibreTexts platform.