What process do hormones use to exert effects on target cells?

Hormones exert their effects on target cells primarily by binding to specific receptors on those cells. This process is vital because it allows hormones to communicate and initiate physiological responses without needing to enter the cell. When a hormone binds to its receptor, it can trigger a cascade of intracellular signaling pathways that result in various cellular responses, such as changes in gene expression, enzyme activity, or ion channel opening.

Each type of hormone has a specific receptor that recognizes and binds only to that hormone, ensuring that the hormone's effects are closely regulated. For instance, steroid hormones often bind to intracellular receptors and influence gene transcription directly, while peptide hormones typically bind to receptors on the cell surface, activating secondary messenger systems within the cell.

This precise interaction between hormones and their receptors underscores the importance of receptor specificity and the variety of mechanisms by which hormones can influence physiological processes.