Many mammals, such as this house mouse, hibernate over the long winter months. Although their metabolism slows during hibernation, the energy needs of the animal must still be met. Fatty acid degradation is a key energy source for this need.
Fatty acids are stored as triacylglycerols in adipose tissue. This fuel-rich tissue is located throughout the body, notably under the skin (subcutaneous fat) and surrounding the internal organs (visceral fat). In this chapter, we will first examine how triacylglycerols are mobilized for use by lipolysis, the degradation of the triacylglycerol into free fatty acids and glycerol. Next, we will investigate how the fatty acids are oxidized to acetyl CoA in the process of β oxidation. We will also study the formation of ketone bodies, a fat-derived fuel source especially important during fasting. Finally, we will investigate the role of fatty acid metabolism in diabetes and starvation.