Steroid hormones primarily bind to receptors inside the cell rather than on the cell surface. Here's why:
1. **Nature of Steroid Hormones:** Steroid hormones are lipophilic (fat-soluble) molecules that can easily pass through the cell membrane due to their structure.
2. **Location of Receptors:** Steroid hormone receptors are found inside the cell, typically in the cytoplasm or nucleus. When a steroid hormone binds to its specific receptor inside the cell, it forms a hormone-receptor complex.
3. **Mechanism of Action:** Once the hormone-receptor complex is formed, it can directly affect gene expression by binding to specific DNA sequences, leading to changes in protein synthesis. This process is known as genomic action.
4. **Examples:** Examples of steroid hormones include cortisol, estrogen, and testosterone. These hormones exert their effects by binding to their respective intracellular receptors and modulating gene expression.
In summary, steroid hormones interact with receptors inside the cell, which allows them to regulate gene expression and influence various physiological processes.
