Lipogenesis in maintenance cultures of rat hepatocytes

Abstract

Induction of the several enzymes in the liver cytosol catalyzing de novo synthesis of fatty acids from glucose has been demonstrated in intact animals. When carbohydrate is provided to previously starved rats the metabolism of liver switches from a gluconeogenic-ketogenic economy to a program facilitating net glycogen and triglyceride synthesis. Induction of the lipogenic enzyme set which commences at least 3 h after carbohydrate alimentation, is preceded by short-term control events which include the accumulation of acetyl precursors (e.g. pyruvate and citrate) that act as positive feed-forward effecters, as well as the relative dephosphorylation of interconvertible enzymes that channel glucose into glycogenesis and lipogenesis. Induction of the lipogenic enzymes seems to be initiated by insulin and counteracted by glucagon (via cAMP).