What is the primary action of testosterone in the body?

• A. Regulating blood pressure
• B. Stimulating hair growth
• C. Promoting sexual development and muscle mass
• D. Inhibiting cortisol production

Answer: (C)

The primary action of testosterone in the body is to promote sexual development and muscle mass. Testosterone is the principal male sex hormone and plays a critical role in the development of male reproductive tissues, such as the testes and prostate, as well as promoting secondary sexual characteristics like increased muscle and bone mass. It influences the development of body hair and contributes to a deeper voice during puberty. Moreover, testosterone enhances muscle protein synthesis, leading to increased muscle strength and size. These effects are crucial for male physical development and overall health, influencing various physiological functions throughout life.

While testosterone can have effects on hair growth, sexual development and muscle building are its most significant functions. The regulation of blood pressure and cortisol production, while important hormonal functions, are not the primary actions of testosterone itself.