Lipogenesis is a metabolic process in animals that converts simple sugars to fatty acids and synthesizes triacylglycerols through the reaction of fatty acids with glycerol. After lipogenesis, the triacylglycerols are packaged into very low-density lipoprotein (VLDL) and secreted by the liver, and they help transport lipids and cholesterol throughout the body. The acetyl-coA molecule begins lipogenesis in the cytoplasm of the body's cells. A complex of enzymes known collectively as fatty acid synthetase completes the fatty acid synthesis.
Carbohydrates form the major bulk of the human diet, and when they are consumed, they must be immediately converted into energy, stored as glycogen, or converted into fat. If the carbohydrates a person eats produce energy in excess of what the body requires for its energy expenditure, lipogenesis converts the excess energy from into body fat, a source of long-term energy. If the carbohydrates consumed do not produce enough energy to support a person's activity level, the energy stored in body fat reserves is used instead.
Balancing one's energy intake through food and energy output through physical activity is the key to weight control. If one consumes too much energy, or calories, lipogenesis will create excess body fat, eventually leading to obesity. Since body fat deposits contain a lot of capillaries, small blood vessels, too much body fat creates a strain on the heart as it must pump extra blood to the fat stores. Obesity can result from overeating or from endocrine gland malfunction.
The acetyl-coA molecule begins the reduction reaction of lipogenesis in the cytoplasm of the body's cells. A complex of enzymes known collectively as fatty acid synthetase completes the fatty acid synthesis. Lipogenesis reactions also require adenosine triphosphate (ATP), the most important nucleotide in intracellular energy transfer.
The hormone insulin, produced in the pancreas, helps to regulate lipogenesis. Insulin is produced in reaction to certain stimuli associated with being fed, including raised glucose levels in the blood and protein ingestion. High glucose levels in the blood also trigger the release of insulin into the bloodstream. Insulin helps to increase a number of storage pathways in the body, including lipogenesis.