BIO200H5 Lecture Notes - Lecture 8: Permeation, Cell Membrane, Extracellular Fluid
Document Summary
Four mechanisms that contribute to variation in drug. If all the sudden, you start making an enzyme in higher concentrations than before, or start making receptor, this can change the concentration of the drug and can lead to a variation in how the drug affects your body. This can lead to changing the clinical response. Can also result from active transport of drug from cytoplasm to extracellular space. This is controlled by multi-drug-resistance proteins which is a transmembrane protein. Ex; p-glycoprotein is over-expressed (the gene coding for the protein transcribed and translated more). This reduces drug concentration inside the cell; this is a major mechanism of how tumor cells develop a resistance to drugs: variation in endogenous ligand concentration: Our body suddenly starts making more of the endogenous ligand concentration. The antagonist competes directly with the endogenous ligand. An endogenous concentration makes response to drug more.
