Integrated Metabolism

1
Integrated Metabolism

• Biochemistry of the organs
• Liver Muscle Kidney
• Heart Brain Adipose
• Communication between organs
• Cori cycle Glucose-Alanine cycle
• Metabolic stress
• Starvation and ketosis
• Diabetes and ketosis

2
Liver (The major anabolic organ)
Biosynthesis of blood constituents
Plasma proteins Gluconeogenesis Glycogen Fatty
acids, triacylglycerols Cholesterol Ketone
bodies VLDL, HDL Urea synthesis Bile salts
Communication with other organs
Target of hormones
Rich in mitochondria
3
Fed Liver
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Fasting Liver
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Brain
Major glucose consumer Limited energy
stores Oxygen dependent Major ATP
producer Consumes glucose and ketone
bodies Hormone insensitive Shielded by BBB
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Heart
Completely aerobic Consumes mostly fat, low
glucose use Mitochondria rich Low energy
reserves Consumes ketone bodies Insulin
insensitive
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Muscle
Uses all fuel sources Exertion uses glucose no
exertion fatty acids Relies on glycogen during
exertion Requires insulin to absorb blood
glucose Major producer of blood
lactate-anaerobic Stores ATP energy as
creatine-PO4 (phosphocreatine)
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Adipose Cells
Major depositors of energy Hormone-sensitive
lipase Insulin-dependent glucose
transport Triacylglycerol synthesis
glucose-dependent Lacks glycerol kinase
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Kidney
10
Pancreas
Secretes digestive enzymes in inactive form Alpha
cells make glucagon Beta cells make insulin Delta
cells make somatostatin Responsive to blood
glucose
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PANCREAS
3 types of cells
Alpha glucagon
Beta Insulin
Delta somatostatin
p. 903
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Communication in Pathways
Glyceraldehyde- 3-phosphate
3-phospho- glycerate
Pyruvate
L-lactate
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Communication within Pathways
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Liver
L-lactate
D-glucose
Blood Glucose
Blood Lactate
THE CORI CYCLE
D-glucose
L-lactate
Muscle
15
Pyruvate
Liver
Gluconeogenesis
D-glucose
L-Alanine
Blood Glucose
Blood Alanine
THE Glucose-Alanine Cycle
L-Alanine
D-glucose
Muscle
Glycolysis
Pyruvate