L carnitine is primarily synthesized in the liver from the amino acids lysine and methionine through a series of four enzymatic reactions, with the liver and kidneys converting the precursor butyrobetaine into active Dietary l Carnitine Supplementation in Obese Cats Alters Carnitine Metabolism and Decreases Ketosis during Fasting and Induced Hepatic Lipidosis ScienceDirect Peculiarities of One Carbon Metabolism in the Strict Carnivorous Cat and the Role in Feline Hepatic Lipidosis L Carnitine Linus Pauling Institute Oregon State University