Correct Option
The correct option is Cortisol.
Explanation
The adrenal glands are paired structures located above the kidneys. Each gland consists of an outer adrenal cortex and an inner adrenal medulla. The adrenal cortex secretes steroid hormones essential for life, which are broadly classified into three groups: mineralocorticoids, glucocorticoids, and sex corticoids.
Option Analysis
- Cortisol Cortisol: Correct. Cortisol is the primary glucocorticoid secreted by the zona fasciculata (the middle layer) of the human adrenal cortex. Its primary functions include regulating carbohydrate metabolism (specifically stimulating gluconeogenesis), maintaining cardiovascular function, and acting as an anti-inflammatory and immunosuppressive agent during long-term stress.
- Aldosterone Aldosterone: Incorrect. Aldosterone is the primary mineralocorticoid, not a glucocorticoid. It is secreted by the zona glomerulosa (the outer layer) of the adrenal cortex. Its main function is to regulate water and electrolyte balance by promoting sodium reabsorption and potassium excretion in the kidneys.
- Estrogen Estrogen: Incorrect. Estrogen is a sex hormone primarily secreted by the ovaries in females. While the zona reticularis (the inner layer) of the adrenal cortex secretes small amounts of androgenic steroids (which can be converted to estrogens), estrogen itself is not classified as a glucocorticoid.
- Oxytocin Oxytocin: Incorrect. Oxytocin is a peptide hormone, not a steroid. It is synthesized in the hypothalamus and released by the posterior pituitary gland (neurohypophysis). It plays a key role in childbirth (uterine contractions) and milk ejection, unrelated to the adrenal cortex.
Key Takeaway
Cortisol is the principal glucocorticoid in humans, produced by the adrenal cortex to regulate glucose metabolism and manage the body's response to stress. Aldosterone is the main mineralocorticoid responsible for salt and water balance.