All Reviews Exceptional Mainstream Art House Indie Family Acting Vehicles Television: Binge, Fringe, or Singe?
Insights Interviews The World of Movies Perfect Reception
Wall of Directors Every Palme d'Or Winner Review Every Academy Award Best Picture Review The Best 100 Films of the 2010's The Best 100 Films of the 2000's The Best 100 Films of the 1990's The Best 100 Films of the 1980's The Best 100 Films of the 1970's The Best 100 Films of the 1960's The Best 100 Films of the 1950's The Best 100 Films of the 1940's The Best 100 Films of the 1930's The Best 100 Films of the 1920's 100 Important Early Films The Best 100 Documentaries of All Time The Best 100 Short Films of All Time The Best 100 Screenplays of All Time The 100 Best Shot Films of All Time The Best 100 Music Videos of All Time The Best 100 Soundtracks of All Time The Best 100 Film Scores of All Time The 100 Best Narrative Television Shows of All Time The Best 100 Television Episodes of All Time 50 Fantastic Non-Narrative/Non-Serialized TV Shows Every Best-Of List
Masterclass Post Script Series
The K Cut TV Sessions Cinemallennials
About Contact Workshops/Seminars
To The Point

Metabolismo De Lipideos -

Introduction

Inside the enterocyte, FFAs and monoacylglycerols are rapidly re-esterified to form TAGs. These, along with newly synthesized cholesteryl esters and phospholipids, are packaged into chylomicrons—the largest and least dense lipoproteins. Chylomicrons enter the lymphatic system (lacteals) and then the bloodstream, delivering dietary lipids to peripheral tissues, particularly adipose tissue and muscle. At the capillary endothelium of these tissues, lipoprotein lipase (LPL) hydrolyzes chylomicron TAGs, releasing FFAs for uptake (storage in adipocytes or oxidation in muscle). The resulting chylomicron remnants, depleted of TAGs, are cleared by the liver via receptor-mediated endocytosis. This hepatic-centric process sets the stage for endogenous lipid metabolism, where the liver produces very-low-density lipoproteins (VLDL) to distribute TAGs synthesized de novo to extrahepatic tissues. metabolismo de lipideos

Lipid metabolism is exquisitely controlled by hormonal and nutritional signals. Insulin promotes anabolism (lipogenesis, TAG storage) and suppresses catabolism (inhibits HSL, activates ACC). Glucagon and epinephrine do the opposite, activating lipolysis and β-oxidation. The AMPK (AMP-activated protein kinase) system acts as a cellular fuel gauge: low energy (high AMP) activates AMPK, which shuts down energy-consuming anabolic pathways (e.g., ACC, HMG-CoA reductase) and turns on catabolic ones (e.g., fatty acid uptake and oxidation). At the capillary endothelium of these tissues, lipoprotein

The journey of dietary lipids begins in the gastrointestinal tract. The hydrophobic nature of triglycerides (TAGs), phospholipids, and cholesterol esters necessitates emulsification by bile salts in the small intestine. Pancreatic lipase, along with its cofactor colipase, then cleaves TAGs into free fatty acids (FFAs) and 2-monoacylglycerols. Phospholipase A2 acts on phospholipids, while cholesterol esterase hydrolyzes cholesterol esters. These breakdown products are incorporated into mixed micelles, which diffuse to the enterocyte brush border for absorption. Lipid metabolism is exquisitely controlled by hormonal and

When energy demands rise or glucose is scarce (e.g., fasting, exercise), fatty acids become the primary fuel. Hormone-sensitive lipase (HSL) in adipose tissue is activated by glucagon and epinephrine, liberating FFAs into the bloodstream. FFAs, bound to serum albumin, are transported to oxidative tissues like heart, skeletal muscle, and liver.

Inside the cell, FFAs are activated to fatty acyl-CoA by acyl-CoA synthetase. The critical entry step into the mitochondria, where β-oxidation occurs, is mediated by the carnitine shuttle. The enzyme carnitine palmitoyltransferase I (CPT1) is the rate-limiting, regulated step; it converts fatty acyl-CoA to acylcarnitine, which is transported across the inner mitochondrial membrane by translocase and then reconverted to acyl-CoA by CPT2. Malonyl-CoA, the first intermediate in fatty acid synthesis, allosterically inhibits CPT1—a prime example of reciprocal regulation between catabolism and anabolism.