9/30 Lipid Digestion and Absorption

Question 1

what are bile salts

Answer 1

modified cholesterol that emulsifies fat and activates digestion of TG. made in pancrease and released into duodenum. help increase the release of FAs

Question 2

orlistat

Answer 2

weight loss drug that inhibits lipase action in the intestinal lumen, so you don’t end up digesting (and hence, absorbing) dietary fat

Question 3

abetalipoproteinemia

Answer 3

AR inherited loss of MTP function, pts are missing chylomicrons, VLDL, and fat-soluable vitamins

same symptoms if loss of ApoB (familial hypobetalipoproteinemia)

CF: caloric deficit, night blindness, neural defects, RBCs with spikes (acanthocytes), spinal defects, steatorrhea

Question 4

hyperchylomicronemia

Answer 4

loss of either LPL or ApoCII, results in a large increase in chylomicrons/TG in blood.

CF: milky pink blood

Question 5

hypertriglyceridemia

Answer 5

high blood TG levels usually from VLDL

deposits of TG seen as eruptive xanthomas, at risk for acute pancreatitis

can lead to high levels of LDL and low levels of HDL

take a fibrate

Question 6

fibrates

Answer 6

gemfibrozil/fenofibrate, lower TG in blood by inducing synthesis of LPL and apoproteins in HDL after activation of PPAR-a. increases FAs in blood

SEs: myopathy and gallstones

Question 7

journey of a TG from mouth to liver

Answer 7

mouth, esophagus, stomach, small intestines, lacteal, lymphatic vessel, thoracic duct, venous system, liver

Question 8

LPL

Answer 8

lipoprotein lipase, in blood, breaks down chylomicrons into FAs that will a) go into tissues, b) go into adipocytes, or c) remnants in blood (chylomicron remnants) will go to liver

expression is increased by insulin (and fibrate drugs)

activated by ApoCII

Question 9

ApoB

Answer 9

critical for the synthesis of chylomicron in the enterocytes (ApoB-48) and VLDL in the liver (ApoB-100), peripheral protein on the lipoprotein

Question 10

MTP

Answer 10

microsomal triglyceride transfer protein, required to make chylomicron in lumen of endoplasmic reticulum of enterocyte, puts TGs/cholesterol/fat-soluable vitamins into chylomicrons

Question 11

ApoCII

Answer 11

aquisition causes maturation of nascent chylomicrons, comes from HDL in the blood, a peripheral apoprotein, needed to activate LPL (coenzyme)

Question 12

ApoE

Answer 12

when LPL in blood breaks down chylomicrons, ApoCII is traded for ApoE w/ HDL. binds to chylomicron remnant receptors and also the liver receptors to initiate receptor-mediated endocytosis

Question 13

ezetimibe

Answer 13

inhibits cholesterol uptake by enterocyte by inhibiting NPC1L1 transporter

Question 14

HDL

Answer 14

high density lipoprotein, transfers cholesterol from tissues to the liver, prevents inappropriate accumulation of cholesterol

Question 15

LDL

Answer 15

low density lipoprotein, derived from VLDL and IDL, delivers cholesterol to peripheral tissues

Question 16

Chylomicron remnants

Answer 16

carry remaining TG, cholesterol, and fat-soluable vitamins

with help of ApoE, taken up by liver

Question 17

IDL

Answer 17

intermediate lipoprotein, from degredation of VLDL and HDL, transports TGs and cholesterol