Ncert Exercises & Solutions

38. Illustrate the differences between the mechanism of action of a protein and a steroid hormone.

Differences between the mechanism of action of a peptide and a steroid hormone are as follows

Peptide Hormone Action

Steroid Hormone Action

Peptide hormones interact with membrane bound receptors.

They generate second messengers (e.g. cyclic AMP, IP₃ ,Ca²⁺ etc.)

The second messengers regulate cellular metabolism.

e.g. oxytocin insulin, glucagon, vasopressin.etc,

They interact with intracellular receptors to form hormonereceptor complex

They regulate gene expression or chromosomes function by the interaction of hormone receptor complex with the genome.

Cumulative biochemical actions results in physiological and development effects.

e.g., cortisol, testosterone, estrogen and progesterone.