Which molecule serves as a common precursor to steroid hormones?

Which molecule serves as a common precursor to steroid hormones?

• A. Cholesterol
• B. Glucose
• C. Amino acids
• D. Nucleotides

Answer: (A)

Steroid hormones all originate from cholesterol. The cholesterol molecule provides the four-ring scaffold that becomes the steroid nucleus, and the mitochondria-specific enzyme cholesterol side-chain cleavage converts cholesterol into pregnenolone, the common starting point for all steroid hormones. From pregnenolone, the body can produce glucocorticoids, mineralocorticoids, and the sex steroids (androgens and estrogens) through various enzymatic steps. The other molecules listed—glucose, amino acids, and nucleotides—are involved in energy, protein, and nucleic acid synthesis, respectively, and are not the shared starting material for steroid hormones.

Steroid hormones all originate from cholesterol. The cholesterol molecule provides the four-ring scaffold that becomes the steroid nucleus, and the mitochondria-specific enzyme cholesterol side-chain cleavage converts cholesterol into pregnenolone, the common starting point for all steroid hormones. From pregnenolone, the body can produce glucocorticoids, mineralocorticoids, and the sex steroids (androgens and estrogens) through various enzymatic steps. The other molecules listed—glucose, amino acids, and nucleotides—are involved in energy, protein, and nucleic acid synthesis, respectively, and are not the shared starting material for steroid hormones.