Module 6 Flashcards
Dominant form of Dietary Fat comprising ~ 90-95% of total energy from fat
a) Phospholipid
b) Sterol
c) TGs
d) TAGs
d) TAG
Which enzyme facilitates TAG digestion into 2 FA +1 MAG?
a) lingual lipase
b) gastric lipase
c) pancreatic lipase
c) pancreatic
Products of complete digestion of TAG: (2)
- glycerol
- FFAs
What does it mean to be an effective detergent? example of one?
- promote solubilisation and absorption of dietary lipids
- Bile acids
What are the primary bile acids? Where are they stored?
a) CA
b) SHP
c) CFA
d) CDCA
e) FXRalpha
a) liver
b) gallbladder
c) small intestine
d) circulating blood
e) large intestine
- a & d; CA and CDCA
- stored in gallbladder (made in liver)
Bile acids can be conjugated with _____ in the liver to increase their water solubility ( called “bile salts”)
a) leucine
b) tyrosine
c) insulin
d) incretin
e) glycine
f) glucose
g) FFAs
e) glycine (or taurine)
- Bile salts (conjugated in liver) can we deconjugated by gut bacteria in the small intestine to form __________
a) Bile Lipids
b) Secondary bile acids
c) Primary bile acids
d) BSHs - Example(s) of these:
a) CA, CDCA
b) CYP7A1, SHP
c) FXR
d) DCA, LCA
e) DCA, DCAC
- b) secondary bile acids
- d) DCA, LCA
Role of Gut bacteria: select all that apply
a) regulates blood lipid and cholesterol levels by influencing recycling
b) conjugation to BSHs
c) deconjugation to BSHs
d) regulated blood glucose and cholesterol levels by influencing recycling
a and c
True or false: primary bile acids are more hydrophobic than secondary
false
Name the primary pathway involved in primary bile acid production
a) Acidic
b) neutral
NEUTRAL PATHWAY
Where is the neutral pathway located, what enzyme is used, what are the products
Liver via CYP7A1
produces CA and CDCA (primary bile acids)
acidic pathway, what enzyme is used, what are the products
Cholesterol converted to oxysterol by CYP27A1 –> travel to liver –> mostly produce CDCA
in enterohepatic regulation, _____ is a bile acid sensor, high bile acid flux activates this, which then activates _____, to suppress ______
FXRalpha, SHP (inhibits LXRalpha), CYP7A1
What is the activator of the neutral pathway
CYP7A1
Bile Acid resins effect on lipid metabolism:
- bind bile acids in digestive tract
- prevent enterohepatic circulation
- hepatic FXRalpha is not activated
- leads to activation of CYP7A1 (neutral pathway)
- inc in conversion of hepatic cholesterol into bile acids and depleted hepatic cholesterol levels –> inc uptake of blood cholesterol into liver
OVERALL RESULT: lowering of total and LDL cholesterol levels in bloods bc of inc uptake into liver
Bile Acid resins effect on glucose metabolism:
- given to T2D’s; improved glycemic control
- 13% reduction in blood glucose
Using an FXR alpha -/- mouse revealed that is regulates _______ and _______
gluconeogenic genes ; HGP
Role of MTP in TAG absorption:
- ensures correct folding of APOB48
- increases with diabetes (it is a pharma target)
Orlistat:
inhibitor
alters fat absorption by inhibiting both pancreatic and gastric ligases directly
blocks intestinal lipid digestion therefore significant body weight reduction and various risk factors
Patients taking orlistat have ______ triglyceride uptake and ______ excretion of fat in feces
a) reduced; reduced
b) increased; reduced
c) reduced; increased
d) increased; increased
c) reduced; increased
Lipid absorption is regulated at 3 stages:
- digestion 2. absorption 3. transport
Enterohepatic circulation
bile acids play a crucial role in fat uptake, cycling between LIVER and GUT
_______ is the link between bile acid biosynthesis, glucose homeostasis and lipogenesis
a) SHP
b) CYP7A1
c) LXR
d) FXRalpha
e) LXRalpha
f)CYP27A1
d) FXR alpha (bile acid sensor)
Targeting lipid absorption with pharmaceutical therapies can _____ uptake of dietary lipids and ______ glucose homeostasis
reduce;improve
