lipids synth- pt2

Question 1

what is elevated haptic SCD1 associated with

Answer 1

increased VLDL synthesis (and
subsequently increased LDL)

Question 2

what is Whole-body SCD1 activity is directly
proportional to

Answer 2

degree of obseity

Question 3

excess SCD1 activity and tumors

Answer 3

Several tumours have excessive oleate
levels due to excess SCD1 activity

Question 4

Excessive SCD1 activity in skin leads to

Answer 4

scaly lesions (combated by dietary 18:2)

Question 5

SCD1 and production of linoleate and linolenate

Answer 5

SCD1 is essential toward the production of
precursors for the synthesis of the
essential fatty acids linoleate and
linolenate, and ultimately arachidonate
and eicosanoid synthesis

Question 6

how is oleate related to SCD1

Answer 6

SCD1 is essential for providing oleate in
myelin synthesis

Question 7

B and T lymphocytes and SCD1

Answer 7

SCD1 is necessary for regulating B- and
T-lymphocyte functions (by modulating
stearate levels)

Question 8

omega 3 FA examples

Answer 8

ALA
EPA
DHA

Question 9

omega 3 and 6 FA benificial or detrimental?

Answer 9

Evidence to date suggests that omega-3 fatty acids are more beneficial than detrimental

omega-6 fatty acids are more detrimental than beneficial

Question 10

examples of omega 6 FA

Answer 10

LA and arachidonate

Question 11

Omega-3 and -6 fatty acids
influence gene transcription

Liver-X-receptor / retinoic acid-X-receptor heterodimer:

Answer 11

– Increase expression of cholesterol efflux
transporters (beneficial), but increases
expression of FAS and SCD1 (detrimentally
leading to hypertriglyceridemia and hepatic
steatosis)

– Oxysterols (derived from cholesterol) activate
LXR/RXR activity

– Omega-3 and -6 fatty acids inhibit oxysterol
activation of LXR/RXR

Question 12

Omega-3 and -6 fatty acids
influence gene transcription

Sterol regulatory element binding protein
(SREBP):

Answer 12

– Increases expression of several elongases
and desaturases, synthesis of FAS, and
synthesis of cholesterol
– SREBP resides on the ER membrane, then is
cleaved, resulting in activation and transport
to the nucleus
– Omega-3 and -6 fatty acids inhibit the
cleavage of SREBP

Question 13

Omega-3 and -6 fatty acids
influence gene transcription

Carbohydrate response element binding
protein (ChREBP):

Answer 13

– Increases expression of FAS
– ChREBP is phosphorylated and needs to be
dephosphorylated to be active
– Omega-3 and -6 fatty acids inhibit the
dephosphorylation of ChREBP

Question 14

Omega-3 and -6 fatty acids
influence gene transcription

Peroxisome proliferator activated receptor
(PPAR) / RXR heterodimer:

Answer 14

– Increases expression of Δ5 and Δ6
desaturases, lipoprotein lipase, proteins
associated with β-oxidation, and improves
insulin sensitivity
– Omega-3 and -6 fatty acids activate the
PPAR/RXR heterodimer

Question 15

what do omega 3 fatty acids do to CVD risk

Answer 15

decrease CVD risk

Question 16

n the nervous system, omega-3 fatty acids:

Answer 16

– Are essential for learning and memory (based
on in vivo studies);
– Increase cellular energy to improve
neurotransmission;
– Stimulates neuronal growth

Question 17

the brain and DHA

Answer 17

The brain loses DHA with age, resulting in increased lipid oxidation, ischemia, inflammation, and amyloid burden

Question 18

Omega 3 and omega 6 FA and eicosanoids

Answer 18

Both omega-3 and omega-6 fatty acids are
used for the synthesis of eicosanoids:
– a class of very potent short-range lipid
signalling molecules involved in pain,
inflammation, regulation of blood pressure,
blood clotting, reproduction, etc.

Question 19

effect of the amount of omega 3 and 6 derived eicosanoids on health

Answer 19

Omega-3 and -6 derived eicosanoids are
important, but excess omega-6
eicosanoids result in excess inflammation
and detrimental outcomes (such as utirine
contraction and premature birth)