Conversion of Cholesterol into Steroid Hormones

• Primary Location: Steroidogenic cells in the adrenal cortex, gonads, and placenta.

Steps Involved:

Conversion of Cholesterol into Steroid Hormones

1. Cholesterol Transport:

• Cholesterol is moved from the outer to the inner mitochondrial membrane by the steroidogenic acute regulatory protein (StAR).

2. Initial Conversion:

• Cholesterol is converted to pregnenolone by the cytochrome P450 side-chain cleavage enzyme (CYP11A1 or P450scc), the rate-limiting step in steroid hormone synthesis.

3. Steroid Hormone Synthesis:

• Pregnenolone is then metabolized into various steroid hormones (glucocorticoids, mineralocorticoids, and sex hormones) through hydroxylation, oxidation, and isomerization.