2. Learning Objectives

2.3. Gene expression regulation enables the human body to respond to changes in nutrient concentration

Hormonal and nutrient concentrations affect several regulatory domains of genes, which encode for enzymes involved in anabolic and catabolic pathways. Insulin and glucose concentrations increase mRNA levels and transcription rates of the glycolytic enzymes, and decrease those of the gluconeogenic enzymes. On the contrary glucagon  has the opposite effect of insulin.

The required protein must be generated at the appropriate time and rate for a cell to function effectively. To prevent the buildup of intermediates, particularly the hazardous ones, in the biosynthetic pathway, the activity of the pathway enzymes must be balanced which could be achieved by regulating the expression of genes encoding these enzymes.