Q.14 Which one of the following hormones is a tyrosine derivative?
(A) Epinephrine
(B) Estradiol
(C) Progesterone
(D) Testosterone

Epinephrine is the correct answer (A).

It serves as the sole tyrosine-derived hormone among the options, synthesized from the amino acid tyrosine in the adrenal medulla.

Option Analysis

Epinephrine (A):
This catecholamine hormone derives directly from tyrosine through hydroxylation to L-DOPA, decarboxylation to dopamine, and further modifications to norepinephrine, then epinephrine via methylation. It triggers the fight-or-flight response by binding adrenergic receptors.

Estradiol (B):
Estradiol belongs to steroid hormones, synthesized from cholesterol via pregnenolone and androstenedione pathways in the ovaries and placenta. It regulates female reproductive functions but lacks tyrosine as a precursor.

Progesterone (C):
Progesterone is a steroid hormone produced mainly in the corpus luteum from cholesterol, supporting pregnancy maintenance. Its structure features four fused rings, unrelated to tyrosine.

Testosterone (D):
Testosterone, another steroid hormone from cholesterol, forms in Leydig cells via progesterone intermediates. It promotes male traits without tyrosine derivation.

Introduction Excerpt

In CSIR NET Life Sciences, identifying the tyrosine derivative hormone epinephrine among options like estradiol, progesterone, and testosterone tests hormone classification knowledge. Epinephrine, derived from tyrosine, powers stress responses, while others stem from cholesterol as steroids.