Drug Targeting (PDE-05) PDF

# Drug Targeting (PDE-05) ## Intracellular Receptors - The chemical messengers for these receptors include steroid hormones, thyroid hormones, and retinoids. - The messenger has to pass through the cell membrane in order to reach its receptor so it has to be **hydrophobic** in nature. - The respon...

# Drug Targeting (PDE-05) ## Intracellular Receptors - The chemical messengers for these receptors include steroid hormones, thyroid hormones, and retinoids. - The messenger has to pass through the cell membrane in order to reach its receptor so it has to be **hydrophobic** in nature. - The response time resulting from the activation of the intracellular receptors is measured in hours or days, and is much slower than the response times of the membrane-bound receptors. - **Duration of response:** Much longer, hours to days. **The intracellular receptors all have similar general structures.** - They consist of a single protein containing a ligand binding site at the C-terminus and a binding region for DNA near the center. The image depicts a cell membrane with various molecules passing through. The molecules include drugs, hormones, nutrition, apolipoproteins & lipoproteins, enzymes, biomarkers, and proteins. The image also depicts the process of signal transduction which starts from the binding of a chemical messenger (ligand) to a receptor, which in turn activates a transcription factor, and ultimately leads to gene expression. The intracellular receptor structure is also depicted in the document. It shows a structure with a zinc finger, a DNA binding region and a steroid receptor binding area.