Figure 1.

Adipocyte metabolism (hypothesis). In the normally hydrated (euhydrated) adipocyte, triglycerides are formed from glucose and free fatty acid uptake, and as well broken down (lipolysis); the rate depending on the needs of the cell for ATP. Glycerol in excess is exported out of the cell. Free fatty acids (ffa) are either metabolized or exported (81). As the adipocyte gets more and more dehydrated, formation of triglycerides increases and the ffa are not able to be transformed into pyruvate and thence metabolized in the mitochondria. The glycerol transporter, aquaporin 9 (AQP9), increases, bringing in more glycerol to make more triglycerides. Glucose uptake is further stimulated by insulin, increasing also triglyceride synthesis. Black circle, cell nucleus; red structure, mitochondria; ffa, free fatty acid; aa, amino acid; AQP7 + 9, aquaporin 7 and 9; HSL, hormone-sensitive lipase.