Essential Biochemistry
This presentation is the property of its rightful owner.
Sponsored Links
1 / 25

Lecture Notes for Chapter 19 Regulation of Mammalian Fuel Metabolism PowerPoint PPT Presentation


  • 222 Views
  • Uploaded on
  • Presentation posted in: General

Essential Biochemistry Third Edition Charlotte W. Pratt | Kathleen Cornely. Lecture Notes for Chapter 19 Regulation of Mammalian Fuel Metabolism. KEY CONCEPTS: Section 19-1. Various organs are specialized for fuel storage, mobilization, and other functions.

Download Presentation

Lecture Notes for Chapter 19 Regulation of Mammalian Fuel Metabolism

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Lecture notes for chapter 19 regulation of mammalian fuel metabolism

Essential Biochemistry

Third Edition

Charlotte W. Pratt | Kathleen Cornely

Lecture Notes for

Chapter 19

Regulation of Mammalian Fuel Metabolism


Key concepts section 19 1

KEY CONCEPTS: Section 19-1

  • Various organs are specialized for fuel storage, mobilization, and other functions.

  • Metabolites travel between tissues in interorgan metabolic pathways.


Cellular locations of major metabolic pathways

Cellular Locations of Major Metabolic Pathways


Organs are specialized for different functions

Organs are specialized for different functions.


Metabolites travel between organs

Metabolites travel between organs.

  • Cori cycle

    • Transport of lactate from muscle to liver

  • Glucose-alanine cycle

    • Pyruvate is produced by muscle glycolysis.

    • Pyruvate is transaminated to make alanine.

    • Alanine is transported from the muscle to the liver.


The cori cycle

The Cori Cycle


The glucose alanine cycle

The Glucose-Alanine Cycle


Key concepts section 19 2

KEY CONCEPTS: Section 19-2

  • Pancreatic cells release insulin in response to increases in circulating glucose.

  • Insulin stimulates the uptake of glucose and the storage of metabolic fuels.

  • Glucagon and epinephrine promote glycogenolysis and lipolysis.

  • Hormones produced by adipose tissue and digestive organs regulate appetite and fuel metabolism.

  • AMP-dependent protein kinase activates ATP-producing pathways and inhibits ATP-consuming pathways.


Insulin shown glucagon and catecholamines are important hormones for fuel metabolism

Insulin (shown), glucagon, and catecholamines are important hormones for fuel metabolism.


Pancreatic islets produce insulin and glucagon

Pancreatic islets produce insulin and glucagon.


Insulin is released in response to glucose

Insulin is released in response to glucose.

  • At physiological conditions, hexokinase is saturated.

  • Glucose phosphorylation by glucokinase varies with glucose concentration.

  • Glucokinase appears to be a glucose sensor, triggering insulin release.


Insulin promotes fuel use and storage

Insulin promotes fuel use and storage.


Impact of insulin on glut4

Impact of Insulin on GLUT4

  • Insulin triggers vesicle fusion to the plasma membrane.

  • Glucose transporter proteins (GLUT4) are presented to the cell surface.


Insulin signaling also impacts glycogen metabolizing enzymes

Insulin signaling also impacts glycogen-metabolizing enzymes.


Glucagon and epinephrine trigger fuel metabolism

Glucagon and epinephrine trigger fuel metabolism.

Structure of Glucagon

  • Glucagon is synthesized and released when blood glucose concentrations drop below 5 mM.


Glucagon and epinephrine trigger fuel metabolism1

Glucagon and epinephrine trigger fuel metabolism.


Amp dependent protein kinase acts as a fuel sensor

AMP-dependent protein kinase acts as a fuel sensor.

Structure of AMPK


Key concepts section 19 3

KEY CONCEPTS: Section 19-3

  • The body breaks down glycogen, fats, and proteins to generate glucose, fatty acids, and ketone bodies during starvation.

  • Obesity appears to result from metabolic, environmental, and genetic factors.

  • In diabetes, either a lack of insulin or the inability to respond to it leads to hyperglycemia.

  • The metabolic syndrome is characterized by obesity and insulin resistance.


The body generates glucose and ketone bodies during starvation

The body generates glucose and ketone bodies during starvation.


Obesity has multiple causes

Obesity has multiple causes.

  • Obesity is impacted by several factors.

    • Diet

    • Metabolism

    • Environmental

    • Genetic

  • The hormone leptin may establish the human body’s set point weight.

  • Distinctions in brown vs. white adipose tissue.


Diabetes is characterized by hyperglycemia

Diabetes is characterized by hyperglycemia.

  • Diabetics excrete large amounts of sugar in their urine.

  • Type 1 diabetes is an autoimmune disease.

  • In Type 2 diabetes, the body does not respond to insulin.


Excess glucose is converted to sorbitol

Excess glucose is converted to sorbitol.


Accumulation of sorbitol in the lens leads to cataract formation

Accumulation of sorbitol in the lens leads to cataract formation.


Antidiabetic drugs work by different mechanisms

Antidiabetic drugs work by different mechanisms.


The metabolic syndrome links diabetes and obesity

The metabolic syndrome links diabetes and obesity.

  • Metabolic syndrome can be characterized by high visceral fat.

  • High levels of dietary fats can lead to:

    • Fat accumulation in adipose tissue

    • Impairment of GLUT4 translocation

    • Impediment of glucose uptake

    • Increased gluconeogenesis

  • Weight loss improves symptoms of metabolic syndrome.


  • Login