Transporter expression refers to the levels of expression of transport proteins within cells. Transporters are proteins that are responsible for moving molecules and ions across cell membranes, allowing for the uptake of essential nutrients and the removal of waste products. The expression of transporters can be influenced by various factors such as cellular signaling pathways, physiological conditions, and external stimuli. Understanding transporter expression is important in various fields of research, including drug development, toxicology, and physiology, as it can impact the absorption, distribution, and elimination of various compounds within the body. Researchers study transporter expression to better understand their roles in cellular function and their potential as therapeutic targets or biomarkers for various diseases.