Question

In fasting or starvation, how are the triglycerides in the adipose tissue metabolized to produce fuel? The breakdown of the triglyceride results in the release of the glycerol into the liver which then can be converted to enter gluconeogenesis making glucose. What about the fatty acids that are released from the triglyceride. Do they become ketones? If so, how and how are the ketones used as fuel?

Answer 1

TRIGLYCERIDES METABOLISM

Triglycerides is an ester derived from glycerol and three fatty acid.Triglycerides consist of a single glycerol molecule and three fatty acids. Triglycerides form by condensation (dehydration) reactions between the hydroxyl (OH) groups of the glycerol and the carboxyl (COOH) group of three fatty acids. Triglycerides are esters being derived from an alcohol .

Triglycerides are also major source of energy in the body.Fatty acids are released between meals from the fat depots in adipose tissue, where they are stored as triglycerides.Fatty acid metabolism involve both catabolic as wellas anabolic processes .In anabolic processes they create biologically important molecoules such as triglycerides , phospholipids, hormones and ketone bodies .

Ketonebodies are the water soluble molecoules containing ketone group that are produced by the liver from fatty acids during fasting, carbohydrate restrictive diets , starvation, prolonged intense exercise ,alcholism ,type1 diabetes mellitus etc.Ketone bodies are transported into tissues outside the liver and converted to acetyl coA, which then enter to citric acid cycle and is oxidised in the mitocondria for energy.

ketone body produced by the liver during starving (above mentioned reason) under go intense gluconeogenesis which is the production glucose from non carbohydrate source.they are therefore always released into the blood by the liver together with newely produced glucose after the liver glycogen store has been depleted ( first 24hours of fasting ).