What is a characteristic of lipid-soluble hormones' mechanism of action?

Lipid-soluble hormones, such as steroid hormones, have a unique mechanism of action primarily because of their chemical structure. These hormones are non-polar and can easily diffuse through the lipid bilayer of cell membranes. This ability to cross the membrane allows them to enter target cells and bind to intracellular receptors located in the cytoplasm or nucleus.

Once bound to their receptors, lipid-soluble hormones typically alter gene expression by influencing RNA synthesis. This mechanism primarily leads to more sustained effects compared to hormones that act through cell-surface receptors, which often trigger quicker cellular responses. The nature of lipid-soluble hormones also means they do not circulate freely in the bloodstream like water-soluble hormones; instead, they often bind to carrier proteins for transport.

Overall, the correct choice reflects the fundamental property of lipid-soluble hormones, highlighting their capacity to permeate cell membranes and engage intracellular signaling pathways.