Question

the mechanism of action of lipid - soluble hormones typically involves what process?
○ binding to receptors on the cell membrane.
○ activation of second messenger systems.
○ directly entering the target cell and binding to intracellular receptors.
○ inducing changes in ion concentrations.
○ promoting the release of neurotransmitters.

Explanation:

Lipid - soluble hormones (such as steroid hormones) can pass through the lipid - bilayer of the cell membrane. They then enter the target cell and bind to intracellular receptors (either in the cytoplasm or nucleus). Binding to cell - membrane receptors (first option) is more typical for water - soluble hormones. Activation of second - messenger systems (second option) is also a mechanism for water - soluble hormones. Inducing changes in ion concentrations (fourth option) is a function of some ion - channel - linked receptors or neurotransmitter - mediated processes. Promoting the release of neurotransmitters (fifth option) is related to neural signaling, not the typical mechanism of lipid - soluble hormones.

Answer:

Directly entering the target cell and binding to intracellular receptors.