The following statement(s) is/are true containing lipid metabolism in the liver
belongs to book: ASIR SURGICAL MCQs BANK|Dr. Gharama Al-Shehri|1st edition| Chapter number:7| Question number:104
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total answers (1)
belongs to book: ASIR SURGICAL MCQs BANK|Dr. Gharama Al-Shehri|1st edition| Chapter number:7| Question number:104
total answers (1)
a. Hepatic mitochondrial hydrolysis of fatty acids is a tremendous source of ATP
c. Approximately 90% of cholesterol synthesis occurs in the liver
The liver has a number of important functions in the metabolism of lipids: 1) the synthesis of apolipoproteins, 2) the degradation of fatty acids into energy substrates, 3) the synthesis of triglycerides from carbohydrates and proteins, and 4) the synthesis of cholesterol and phospholipids from fatty acids. The mitochondrial hydrolysis of fatty acids is a source of large quantities of ATP. The conversion of stearic acid to CO2 and H2O, for instance, generates 136 ATP molecules and demonstrates the highly efficient storage of energy in fat. In times of unrestrained lipolysis, such as starvation, uncontrolled diabetes or other conditions of triglyceride mobilization from adipose tissue, the ability of the liver to perform beta-oxidation may be inadequate. Under these circumstances, significant hepatic storage of triglycerides or fatty infiltration of the liver may occur. Triglyceride storage by itself does not appear to be a cause of hepatic fibrosis or necrosis, but fatty infiltration may be a marker for derangement of normal processes by alcohol or drug toxicity, diabetes, chronic parenteral nutrition, or morbid obesity
Cholesterol is an important regulator of membrane fluidity and is a substrate for bile acid and steroid hormone synthesis. Cholesterol may be available by dietary intake or by de novo synthesis. In mammals, about 90% of new cholesterol is synthesized by the liver from its precursor, acetyl CoA. Dietary cholesterol intake suppresses endogenous synthesis by inhibiting the rate-limiting enzyme in cholesterol by a synthetic pathway, HMG-CoA reductase. There are three major classes of phospholipids synthesized by the liver: the lecithins, the cephalins, and the sphingomyelins. Although most cells in the body are capable of some phospholipid synthesis, the liver produces 90%.
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