Where are lipid-soluble hormone receptors typically located?

• A. On the outer surface of the plasma membrane
• B. Usually inside cell
• C. In the extracellular matrix
• D. In the lysosome

Answer: (B)

Lipid-soluble hormones cross the cell membrane and bind to receptor proteins inside the cell, typically in the cytoplasm or the nucleus. When the hormone binds, the receptor–hormone complex often acts as a transcription factor, turning genes on or off and producing slower, longer-lasting effects. This intracellular location contrasts with water-soluble hormones, which bind to receptors on the cell surface because they can’t readily cross the membrane and instead trigger rapid signaling cascades. Receptors in the extracellular matrix or lysosomes aren’t how lipid-soluble signals are conveyed.