PDK4 and cardiac hypertrophy: In a previous study [13], the protective role of L-glutamine supplementation on gestational fructose-induced cardiac hypertrophy was related to an increase in pyruvate dehydrogenase kinase 4 (PDK4), an enzyme that regulates the entry of glycolytic products into the citric acid cycle, preventing the complete oxidation of glucose and promoting glycogen and lipid accumulation.