Biology teacher

  Mechanism of Hormone Action – Easy NEET Notes Introduction Hormones regulate different physiological activities of the body. Based on their chemical nature, hormones are divided into four groups. Types of Hormones 1. Peptide / Polypeptide / Protein Hormones Examples Insulin Glucagon Pituitary hormones Hypothalamic hormones Important Features Made up of amino acids. Water soluble. Cannot pass through cell membrane. Act through membrane-bound receptors. NEET Point These hormones use second messengers like: cAMP IP₃ Ca²⁺ 2. Steroid Hormones Examples Cortisol Testosterone Estradiol Progesterone Important Features Lipid soluble. Can easily pass through plasma membrane. Receptors are inside the cell. NEET Point They directly influence: Gene expression Protein synthesis 3. Iodothyronines (Thyroid Hormones) Examples T₃ (Triiodothyronine) T₄ (Thyroxine) Important Features Derived from amino acid tyrosine. Regulate metabolism and ...