Carnitine is a quaternary ammonium compound that transports fatty acids into mitochondria for energy production. It is biosynthesized from the amino acids lysine and methionine in the liver and kidneys. Carnitine carries long-chain fatty acids into mitochondria, where they undergo beta-oxidation to produce acetyl-CoA for the citric acid cycle. Carnitine supplements are used to treat heart conditions, kidney disease, male infertility, weight loss, valproic acid poisoning, asthma, cancer chemotherapy side effects, and hyperthyroidism.

1. CARNITINE BIOSYNTHESIS,
UTILISATION AND ITS USE
IN MEDICINE
MUNIVENKATESH.P
GROUP 2

2. Carnitine
Carnitine is a quaternary ammonium
compound.
In living cells, it is required for the transport
of fatty acids from the cytosol into the
mitochondria during the breakdown
of lipids (fats) for the generation of metabolic
energy
 It is widely available as a nutritional
supplement

3. Carnitine was originally found as a growth
factor for mealworms and labelled
vitamin BT, although carnitine is not a
proper vitamin
Carnitine exists in two stereo isomers: Its
biologically active form is L-carnitine, whereas
its enantiomer, D-carnitine, is biologically
inactive

4. Systematic iupac name
3-hydroxy-4-(trimethylazaniumyl)butanoate

5. In animals, the biosynthesis of carnitine occurs
primarily in the liver and kidneys from the
amino acids lysine (via trimethyllysine) and
methionine
It is a method for the endogenous production
of L-carnitine, a molecule that is essential
for energy metabolism
Carnitine biosynthesis

7. Utilization of carnitine
Carnitine transports long-chain acyl groups
from fatty acids into the mitochondrial matrix,
so they can be broken down through β-
oxidation to acetyl CoA to obtain usable
energy via the citric acid cycle
Fatty acids must be activated before binding
to the carnitine molecule to form
'acylcarnitine'.

9. The free fatty acid in the cytosol is attached
with a thioester bond to coenzyme A (CoA).
This reaction is catalyzed by the enzyme fatty
acyl-CoA synthetase
The acyl group on CoA can now be transferred
to carnitine and the resulting acylcarnitine
transported into the mitochondrial matrix.
This occurs via a series of similar steps

10. • Acyl CoA is transferred to the hydroxyl group
of carnitine by carnitine acyltransferase
I (palmitoyltransferase) located on the outer
mitochondrial membrane
• Acylcarnitine is shuttled inside by a carnitine-
acylcarnitine translocase
• Acylcarnitine is converted to acyl CoA
by carnitine acyltransferase
II (palmitoyltransferase) located on the inner
mitochondrial membrane. The liberated
carnitine returns to the cytosol.

13. Uses of carnitine
Heart conditions
Kidney disease and dialysis
Effect in male infertility
As a weight loss supplement
As an antidote in valproic acid poisoning
To improve symptoms in moderate asthmatics
To improve fatigue resulting from ifosfamide
cancer chemotherapy
To treat symptoms of hyperthyroidism

14. Heart conditions
Carnitine is primarily used for heart-related conditions.
Several clinical trials show that L-carnitine and propionyl-
L-carnitine can be used along with conventional
treatment for angina to reduce medication needs and
improve the ability of those with angina to exercise
without chest pain. There are conflicting studies
concerning the use of carnitine after a heart attack. While
some studies suggest people taking L-carnitine may be
less likely to suffer a subsequent heart attack or
experience chest pain and abnormal heart rhythms, other
studies have not found similar benefits.

15. Kidney disease and dialysis
Because kidneys produce carnitine, kidney disease may
lead to the deficiency of carnitine in the body. Thus,
carnitine may be prescribed to those with kidney disease

16. Effect in male infertility
The use of carnitine showed some promise in a
controlled trial in selected cases of male infertility by
improving sperm quality. L-Carnitine supplementation
has also shown to have beneficial effects in the
treatment of varicocele, a major cause of male infertility

17. As a weight loss supplement
There is no scientific evidence to show it improves weight
lose, still some studies show that, oral carnitine reduces
fat mass, increases muscle mass and reduces fatigue
All these effects indirectly lead to weight lose

18. As an antidote in valproic acid poisoning
In the treatment of valproate toxicity, L-carnitine
supplementation ...is thought to provide benefit,
particularly in patients with concomitant
hyperammonemia, encephalopathy, and/or
hepatotoxicity

19. To improve symptoms in moderate asthmatics
L-Carnitine levels are lower in moderate persistent
asthmatic children as compared to healthy control
children. Asthmatic children who received L-carnitine
supplementation for six months showed statistically
significant improvement in their 'asthma control testing'
and in their pulmonary function tests

20. To improve fatigue resulting from ifosfamide
cancer chemotherapy
High doses of the chemotherapy agent ifosfamide, due to
its potential nephrotoxicity, may cause urinary loss of
carnitine. One study suggests, as it is essential for energy
production by mitochondria, L-carnitine may have a role
in reducing ifosfamide-associated fatigue

21. To treat symptoms of hyperthyroidism
L-Carnitine is a peripheral antagonist of thyroid hormone
action. It inhibits the entry of triiodothyronine and
thyroxine into the cell nuclei. In a randomized trial it was
shown that 2–4 g of oral L-carnitine per day could
reverse hyperthyroid symptoms even in the most serious
form of hyperthyroidism, thyroid storm. Since
hyperthyroidism impoverishes the tissue deposits of
carnitine, there is a rationale for using L-carnitine at
least in certain clinical settings. Incidentally, the fact that
carnitine failed to prevent relapses of hyperthyroidism
further supports the concept that carnitine action is in
the periphery and not in the thyroid gland.