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Editorial: Leptin - The Central Regulator of Starvation
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Vidisha Raje, PhD
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University of Virginia
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Department of Pharmacology, UVA, Charlottesville, Virginia 22903, USA
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vbr9n@virginia.edu
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Humans have evolved to store energy in three major forms: carbohydrate, fat, and protein. In the liver, insulin triggers the storage of circulating glucose as glycogen, which can be readily mobilized to glucose and is the fuel of choice where instantaneous energy is required, such as during conditions of stress and the onset of starvation. However, liver glycogen accounts for <1% of the total stored energy. Skeletal muscle is also a major site of storage of glycogen (about 2/3 of the total glycogen) and protein and accounts for 15% of the total stored energy. The majority of energy stores, >80%, are in the form of fat, stored as lipid droplets in adipocytes1. Teleologically, this makes a lot of sense given that humans have been hunter-gatherers and had to go for prolonged periods of starvation in search of food. On the contrary, the modern man is exposed to a much more nutrient replete environment. The human body, however, is still adapted for efficiently storing any ingested nutrients as energy reserves in different tissues for periods of critical need such as starvation.
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