Which enzyme in the adrenal cortex is stimulated by ACTH?

The cholesterol side chain cleavage enzyme, also known as CYP11A1, is the enzyme in the adrenal cortex that is directly stimulated by ACTH (adrenocorticotropic hormone). This enzyme is responsible for the conversion of cholesterol into pregnenolone, the first step in the biosynthesis of steroid hormones in the adrenal cortex. The activation of this enzyme by ACTH increases the production of glucocorticoids, mineralocorticoids, and adrenal androgens, ultimately impacting various physiological processes.

This process is part of the body's response to stress, where ACTH stimulates the adrenal cortex to produce hormones that help regulate metabolism, immune response, and blood pressure. Understanding this mechanism is crucial when studying endocrine function and adrenal gland pathophysiology.