Correct Option
The correct option is Adrenaline.
Explanation
Hormones are classified chemically into distinct categories such as steroids, peptides, and amines. Catecholamines are a specific subset of amine hormones derived from the amino acid tyrosine. They are primarily secreted by the adrenal medulla and nerve endings of the sympathetic nervous system.
Option Analysis
- Adrenaline (Epinephrine): This hormone is secreted by the adrenal medulla during the "fight or flight" response. Chemically, it is an amine derived from tyrosine and contains a catechol group, classifying it as a catecholamine. Other major catecholamines include noradrenaline (norepinephrine) and dopamine.
- Cortisol: This is a glucocorticoid secreted by the adrenal cortex. Chemically, it is a steroid hormone derived from cholesterol, not an amine.
- Aldosterone: This is a mineralocorticoid secreted by the adrenal cortex. Like cortisol, it is a steroid hormone involved in salt and water balance.
- Estrogen: This is a primary female sex hormone produced mainly by the ovaries. It is chemically classified as a steroid hormone.
Key Takeaway
Adrenaline and Noradrenaline are catecholamines (water-soluble, amino acid derivatives), whereas Cortisol, Aldosterone, and Estrogen are steroid hormones (lipid-soluble, cholesterol derivatives).