GCG and Cirrhosis: The strongest and most important upregulator is glucagon, which is involved in moment-to-moment regulation via its effects on N-acetyl-glutamate and in long-term regulation via induction of the urea cycle genes.[36], [37], [38] Downregulation of glucagon by glucose and its insulin response is responsible for the fall in urea synthesis and body nitrogen loss following carbohydrate ingestion, an effect lost in cirrhosis.34