What is the difference between endogenous and exogenous cholesterol

Monoglycerides, FFAs, and free cholesterol are then solubilized in the intestine by bile acid micelles, which shuttle them to intestinal villi for absorption.

Once absorbed into enterocytes, they are reassembled into TGs and packaged with cholesterol into chylomicrons, the largest lipoproteins. Chylomicrons transport dietary TGs and cholesterol from within enterocytes through lymphatics into the circulation. Cholesterol-rich chylomicron remnants then circulate back to the liver, where they are cleared in a process mediated by apoprotein E apo E.

Lipoproteins synthesized by the liver transport endogenous triglycerides and cholesterol. Lipoproteins circulate through the blood continuously until the TGs they contain are taken up by peripheral tissues or the lipoproteins themselves are cleared by the liver.

Factors that stimulate hepatic lipoprotein synthesis generally lead to elevated plasma cholesterol and TG levels. Very-low-density lipoproteins VLDL contain apoprotein B apo B , are synthesized in the liver, and transport TGs and cholesterol to peripheral tissues. Complications include cardiovascular disorders particularly in people with excess abdominal fat , diabetes mellitus Early symptoms are related to hyperglycemia and include polydipsia Hepatic LDL receptors are down-regulated by delivery of cholesterol to the liver by chylomicrons and by increased dietary saturated fat; they can be up-regulated by decreased dietary fat and cholesterol.

Nonhepatic scavenger receptors, most notably on macrophages, take up excess LDL not processed by hepatic receptors. Monocytes migrate into the subendothelial space and become macrophages; these macrophages then take up oxidized LDL and form foam cells within atherosclerotic plaques Pathophysiology Atherosclerosis is characterized by patchy intimal plaques atheromas that encroach on the lumen of medium-sized and large arteries; the plaques contain lipids, inflammatory cells, smooth muscle The size of LDL particles varies from large and buoyant to small and dense.

Small, dense LDL is especially rich in cholesterol esters and is associated with metabolic disturbances such as hypertriglyceridemia and insulin resistance. High-density lipoproteins HDL are initially cholesterol-free lipoproteins that are synthesized in both enterocytes and the liver.

HDL metabolism is complex, but one role of HDL is to obtain cholesterol from peripheral tissues and other lipoproteins and transport it to where it is needed most—other cells, other lipoproteins using cholesteryl ester transfer protein [CETP] , and the liver for clearance.

Its overall effect is anti-atherogenic. Incidence of coronary heart disease events in a normal population is inversely related to the serum HDL-cholesterol concentration - low levels carry an increased coronary risk. This effect may be mediated by reverse cholesterol transport, a process whereby excess cholesterol in cells and in atherosclerotic plaques is removed and transported back to the liver.

Low HDL-cholesterol is a component of the metabolic syndrome that is characterized by obesity, insulin resistance, dyslipidemia, and hypertension.

Exercise, weight loss in overweight subjects , smoking cessation, and changes in diet specifically substitution of monounsaturated for saturated fatty acids all can raise HDL-cholesterol. Obesity, Overweight, and Dyslipidemia in Children and Adolescents. Major lipoproteins include: Chylomicrons - large particles that carry dietary lipid Very low density lipoprotein - carry endogenous triglyceride and some cholesterol Intermediate density lipoprotein - carry cholesterol esters and triglycerides Low density lipoprotein - carry cholesterol esters High density lipoprotein - carry cholesterol esters Exogenous pathway for lipid metabolism: Dietary cholesterol and fatty acids are absorbed.

Triglycerides are formed in the intestinal cell from free fatty acids and glycerol and cholesterol is esterified. Triglycerides and cholesterol combine to form chylomicrons. Thereof, what is exogenous fat? It is divided into two pathways, exogenous and endogenous, depending in large part on whether the lipoprotein particles in question are composed chiefly of dietary exogenous lipids or whether they originated in the liver endogenous , through de novo synthesis of triacylglycerols.

Secondly, what are the two sources of cholesterol in the human body? Cholesterol in your body comes from two main sources: your liver and your diet. Your liver , other organs, and other cells in your body produce about 75 percent of the cholesterol in your blood.

The other 25 percent of cholesterol in your body is affected by the foods you eat. Cholesterol is recycled in the body. The liver excretes cholesterol into biliary fluids, which is then stored in the gallbladder, which then excretes it in a non-esterified form via bile into the digestive tract. Intestinal triglycerides are derived from both endogenous and exogenous sources. The different patterns in the partition of endogenous and exogenous triglyceride into chylomicrons and VLDL suggest that these two lipid-carrying lipoproteins are probably packaged differently in the small intestine.

Asked by: Maravilla Antas healthy living nutrition What is the difference between endogenous and exogenous cholesterol? Last Updated: 2nd September, In the endogenous path- way, cholesterol is synthesized by the liver and extra- hepatic tissues and secreted into plasma, whereas the intestine is the primary site of the exogenous pathway of dietary cholesterol uptake[1—3]. Alteration of either path- way will affect the concentration of plasma cholesterol.

Truman Olaverria Professional. What are the 5 types of lipoproteins? There are five different types of lipoproteins in the blood, and they are commonly classified according to their density.

Kaitlyn Xillo Professional. Which lipoprotein has the highest percentage of cholesterol? Table 2. Ihssane Kalitvintsev Professional. Is cholesterol a phospholipid? Cholesterol is referred as an amphipathic molecule, that it contains its hydrophilic and hydrophobic parts. The hydroxyl group -OH in cholesterol is aligned with the phosphate head of the phospholipid on cell membrane, which the rest of the cholesterol goes with the fatty acid of the membrane.

Shalini Tosolini Explainer. What are the 4 types of lipoproteins? Classification and formation. There are four major classes of circulating lipoproteins , each with its own characteristic protein and lipid composition.

Yineth Tiefensee Explainer. What is the exogenous pathway? The exogenous pathway is utilized by specialized antigen-presenting cells to present peptides derived from proteins that the cell has endocytosed. Proteins are endocytosed and degraded by acid-dependent proteases in endosomes; this process takes about an hour.