Functional glycerol kinase activity and the possibility of a major role for glyceroneogenesis in mammalian skeletal muscle

According to textbook descriptions of glycerol metabolism, liver and kidney are the only tissues that express significant glycerol kinase activity Thu s esterification of fatty acids to triglycerides in peripheral tissues such as skeletal muscle and adipose tissue is presumed to be dependent on the s ynthesis of glycerol-3-phosphate from glucose. This report describes exciti ng new data indicating that, although low, the glycerol kinase activity of skeletal muscle is functional. Interestingly, the results also suggest that neither glycerol nor glucose is the major substrate for the synthesis of m uscle triglyceride glycerol. Rather, glyceroneogenesis, the synthesis of gl ycerol-3- phosphate from lactate, may play an as yet underappreciated, but quantitatively important, role.