Hormonal regulation of gluconeogenic gene transcription in the liver.

Glucose homeostasis in mammals is achieved by the actions of counterregulatory hormones, namely insulin, glucagon and glucocorticoids. Glucose levels in the circulation are regulated by the liver, the metabolic centre which produces glucose when it is scarce in the blood. This process is catalysed by two rate-limiting enzymes, phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) whose gene expression is regulated by hormones. Hormone response units (HRUs) present in the two genes integrate signals from various signalling pathways triggered by hormones. How such domains are arranged in the regulatory region of these two genes, how this complex regulation is accomplished and the latest advancements in the field are discussed in this review.