[ppt]lipid transport & storage - qums.ac.ireprints.qums.ac.ir/302/1/lipid transport &...

Lipid Transport Lipid Transport and Storageand Storage

05/06/23 02:53 Lipid transport & storage 2

LIPIDS ARE TRANSPORTED IN LIPIDS ARE TRANSPORTED IN THE PLASMA AS THE PLASMA AS LIPOPROTEINSLIPOPROTEINS

Lipoproteins Consist of a Nonpolar Core & a Single Surface Layer of Amphipathic Lipids

The Distribution of Apolipoproteins Characterizes the Lipoprotein

05/06/23 02:53 Lipid transport & storage 3

FREE FATTY ACIDSFREE FATTY ACIDS ARE RAPIDLY ARE RAPIDLY METABOLIZEDMETABOLIZED

TRIACYLGLYCEROLTRIACYLGLYCEROL IS IS TRANSPORTED FROM THE TRANSPORTED FROM THE INTESTINES IN CHYLOMICRONS & INTESTINES IN CHYLOMICRONS & FROM THE LIVER IN VERY LOW FROM THE LIVER IN VERY LOW DENSITY LIPOPROTEINSDENSITY LIPOPROTEINS

05/06/23 02:53 Lipid transport & storage 4

05/06/23 02:53 Lipid transport & storage 5

Composition of the lipoproteinslipoproteins in plasma of humans.

05/06/23 02:53 Lipid transport & storage 6

CHYLOMICRONSCHYLOMICRONS & VLDLVLDL ARE RAPIDLY CATABOLIZED

Triacylglycerols of Chylomicrons & VLDL Are Triacylglycerols of Chylomicrons & VLDL Are Hydrolyzed by Hydrolyzed by Lipoprotein LipaseLipoprotein Lipase

The Action of Lipoprotein Lipase Forms The Action of Lipoprotein Lipase Forms Remnant LipoproteinsRemnant Lipoproteins

The The LiverLiver Is Responsible for the Uptake of Is Responsible for the Uptake of Remnant LipoproteinsRemnant Lipoproteins

05/06/23 02:53 Lipid transport & storage 7

Metabolic fate ofMetabolic fate of chylomicronschylomicrons

05/06/23 02:53 Lipid transport & storage 8

Metabolic fate of Metabolic fate of VLDLVLDL and production of and production of LDLLDL

05/06/23 02:53 Lipid transport & storage 9

LDLLDL IS METABOLIZED VIAIS METABOLIZED VIATHE THE LDL RECEPTORLDL RECEPTOR

05/06/23 02:53 Lipid transport & storage 10

HDLHDL TAKES PART IN BOTH TAKES PART IN BOTHLIPOPROTEIN LIPOPROTEIN TRIACYLGLYCEROLTRIACYLGLYCEROL

& & CHOLESTEROLCHOLESTEROL METABOLISM METABOLISM

05/06/23 02:53 Lipid transport & storage 11

CLINICAL ASPECTSCLINICAL ASPECTS

Imbalance in the Rate of TG Formation & Export Causes Fatty LiverFatty Liver

Ethanol Also Causes Fatty LiverFatty Liver

05/06/23 02:53 Lipid transport & storage 12

ADIPOSE TISSUEADIPOSE TISSUE IS THE MAIN STOREOF TGTG IN THE BODY

The Provision of Glycerol 3-PhosphateGlycerol 3-Phosphate Regulates Esterification: Lipolysis Is Controlled by Hormone-Sensitive LipaseHormone-Sensitive Lipase (Figure 25–7)

Increased GlucoseGlucose Metabolism Reduces the Output of Free Fatty Acids

05/06/23 02:53 Lipid transport & storage 13

05/06/23 02:53 Lipid transport & storage 14

HORMONESHORMONES REGULATEFAT MOBILIZATION

InsulinInsulin Reduces the Output of Free Reduces the Output of Free Fatty AcidsFatty Acids

Several HormonesSeveral Hormones Promote Lipolysis Promote Lipolysis

05/06/23 02:53 Lipid transport & storage 15

LipolysisLipolysis increased by:

Epinephrine Norepinephrine Glucagon ACTH TSH Thyroid hormone

GH MSH Vasopressin Caffeine Theophylline Leptin

05/06/23 02:53 Lipid transport & storage 16

LipolysisLipolysis decreased by:

Insulin Nicotinic acid Prostaglandin E1

05/06/23 02:53 Lipid transport & storage 17

BROWN ADIPOSEBROWN ADIPOSE TISSUE TISSUEPROMOTES PROMOTES THERMOGENESISTHERMOGENESIS

Brown adipose tissue is involved in metabolism particularly at times when heat generation is necessary

Though not a prominent tissue in humans, it is present in normal individuals, where it could be responsible for “diet-induced thermogenesis.”

It is noteworthy that brown adipose tissue is reduced or absent in obese persons.

05/06/23 02:53 Lipid transport & storage 18

The tissue is characterized by: well-developed bloodblood supply

high content of mitochondriamitochondria and cytochromescytochromes

but low activitylow activity of ATP synthase.

A thermogenic uncoupling protein, thermogeninthermogenin, acts as a proton conductance pathway dissipating the electrochemical potential across the mitochondrial membrane

05/06/23 02:53 Lipid transport & storage 19

Thermogenesis increased by:

NorepinephineNorepinephine

FFAFFA

Acyl-CoAAcyl-CoA

05/06/23 02:53 Lipid transport & storage 20

Thermogenesis decreased by:Thermogenesis decreased by:

Purine nucleotidesPurine nucleotides

05/06/23 02:53 Lipid transport & storage 21

THE ENDTHE END