Which of the following hormone acts via an intracellular receptor mechanism?

 # Which of the following hormone acts via an intracellular receptor mechanism?

A. Insulin

B. Epinephrine

C. Cortisol

D. Glucagon

The correct answer is C. Cortisol.

Cortisol acts via an intracellular receptor mechanism. It is a steroid hormone that binds to glucocorticoid receptors inside the cell, affecting gene expression.

Explanation:

• Insulin (A) and Glucagon (D) are peptide hormones that bind to cell surface receptors (tyrosine kinase and G-protein-coupled receptors, respectively), triggering extracellular signaling pathways.
• Epinephrine (B) is a catecholamine that also acts through cell surface G-protein-coupled receptors (e.g., adrenergic receptors).
• Cortisol (C), a steroid hormone, crosses the cell membrane and binds to intracellular glucocorticoid receptors, forming a complex that translocates to the nucleus to regulate gene transcription.

Thus, the correct answer is C. Cortisol.