This document discusses how different organs regulate metabolism to maintain energy balance. The liver regulates sugar and fat storage and breakdown. The kidneys help produce glucose during starvation. Hormones like epinephrine, insulin, and glucagon signal the liver and muscles to store or release sugars and fats. Prolonged starvation causes the body to use ketone bodies instead of glucose for fuel. Uncontrolled diabetes occurs when cells cannot respond to insulin signals, leading to high blood sugar and dangerous ketone production. Dieting aims to mimic controlled starvation for weight loss but requires supervision.

1. Metabolic interrelationship
Chapter 6:
Integration, Specialization, and Regulation of
Metabolism

2.  At this point, we’ll
consider how
organisms
arrange/organize the
metabolic symphony
to meet their energy
needs.
 Discussion will
include how:
 Body maintains
energy balance
(homeostasis)
 It deals with
starvation
 It responds to the
loss of control from
diabetes mellitus

3. Table 24-2, p.666

4. Food pyramid
Fig. 24-2, p.668

5.  Review of
metabolism
 Glycolysis
 Gluconeogenesi
s
 The pentose
phosphate
pathway
 Β oxidation and
fatty acids
synthesis
 Amino acids
degradation
and synthesis
 The citric acid
cycle
 Oxidative
phosphorylatio
n

9. Brain

10. Muscle

11. Liver

12.  The liver can synthesize or degrade TAGs
 When metabolic fuel is needed, f.acids are degraded
to acetyl-CoA and then to ketone bodies (export via
bloodstream to the peripheral tissues)
 When the demand is low, f.acids are used to
synthesize TAGs (secreted into the bloodstream as
VLDL for uptake by adipose tissue)
 Amino acids are important metabolic fuel
The liver degrades amino acids to a variety of
intermediates (begin with a.acid transamination to
yield α-keto acid, via urea cycle excreted urea)
Glucogenic a.acid – converted to pyruvate / OAA
(TCA cycle intermediates)
Ketogenic a.acid – converted to ketone bodies

13. Kidney  Overall reaction in
kidney: Glutamine →
α-ketoglutarate +
 Functions NH4+
: to filter out the waste  During starvation, the
product urea from the α-ketoglutarate enters
bloodstream gluconeogenesis
: to concentrate it for (kidneys generate as
excretion much as 50% of the
body’s glucose supply)
: to recover important
metabolites (glucose)
 α-ketoglutarate :
converted to malate
: to maintain the blood (TCA cycle)
pH
: pyruvate (oxidized to
CO2) or via OAA to PEP
: converted to glucose
via gluconeogenesis

17. Hormones reacts as the intercellular messengers
Hormones transported from the sites of their synthesis to
the sites of action by the bloodstream
Fig. 24-5, p.671

18.  Some typical
hormones:
- steroids
(estrogens,
androgens)
- polypeptides
(insulin and
endorphins)
- a.acid derivatives
(epinephrine and
norepinephrine)
 Hormones help
maintaining
homeostasis (the
balance of biological
activities

19. Table 24-3, p.672

20.  The effects of hormones triggered
the responses within the cell
 There are three hormones play a
part in the regulation of CHO
metabolism
 Epinephrine, insulin and glucagon
 Epinephrine: acts on muscle tissue,
to raise level of glucose on
demand, when it binds to specific
receptors, it leads to increased
level of glucose in blood, increased
glycolysis in muscle cells and
increased breakdown of f.acid for
energy
p.681

21. Fig. 24-14, p.682

22.  Glucagon: acts on
liver, to increase
the availability of
glucose, when it
binds to specific
receptors, it leads
to increased level
of glucose in
blood.

26. Table 24-4, p.685

32.  During prolonged starvation or fasting, the brain slowly
adapts from the use of glucose as its soul fuel source to the
use of ketone bodies, shift the metabolic burden form
protein breakdown to fat breakdown
 Diabetes mellitus is a disease in which insulin either not
secreted or doesn’t stimulate its target tissues → high
[glucose] in the blood and urine. Abnormally high
production of ketone bodies is one of the most dangerous
effects of uncontrolled diabetes
 Dieting – to lose excess weight. Diet forced the body to
follow the same adjustment like starvation or fasting but a
more moderate or controllable pace. Dieting is not free of
problems, therefore it is advisable to undergo diet under
supervision of physician or nutritionist.