Basic concepts of endocrine system.power point presentation

B. pharmacy
5th sem
unit IV
Pharmacology-II

1. Pharmacology of drugs acting on endocrine system Basic concepts in endocrine pharmacology. MR . JAGDEEP SINGH M. PHARMACY (PHARMACOLOGY) ASSISTANT PROFESSOR AT GLOBAL RESEARCH INSTITUTE OF PHARMACY, RADAUR, YAMUNANAGAR

2. INTRODUCTION TO ENDOCRINE PHARMACOLOGY Endocrine System : A network of glands that produce and release hormones to regulate body functions. Hormones : Chemical messengers that influence metabolism, growth, reproduction, and homeostasis (stable internal conditions). PHARMACOLOGY OF THE ENDOCRINE SYSTEM INVOLVES: Hormone Analogues (Synthetic versions of natural hormones used as replacement therapy). Hormone Inhibitors (Drugs that block hormone production or action in cases of excess hormone secretion). Justification: The endocrine system maintains body homeostasis. Understanding pharmacology helps in treating hormonal imbalances.

3. ENDOCRINE GLANDS AND THEIR HORMONES GLAND HORMONES SECRETED FUNCTION Hypothalamus Releasing & Inhibiting Hormones Controls the pituitary gland Pituitary Gland GH, TSH, ACTH, FSH, LH, PRL Regulates other endocrine glands Thyroid Gland T3, T4, Calcitonin Regulates metabolism, calcium levels Parathyroid Gland Parathyroid Hormone (PTH) Regulates calcium levels Adrenal Gland Cortisol, Aldosterone, Epinephrine Stress response, metabolism, BP control Pancreas Insulin, Glucagon Blood sugar regulation Ovaries/Testes Estrogen, Progesterone, Testosterone Reproductive functions Justification: Different glands produce specific hormones to regulate physiological processes. Their dysfunction leads to metabolic disorders.

4. Hormone Classification Peptide Hormones (Protein-based, act on cell surface receptors) Examples: Insulin, Growth Hormone (GH), TSH Steroid Hormones (Lipid-based, act on intracellular receptors) Examples: Cortisol, Estrogen, Testosterone Amino Acid-Derived Hormones (Derived from Tyrosine) Examples: Thyroid Hormones (T3, T4), Epinephrine, Dopamine Justification: Understanding hormone structure helps in drug design, as receptor interactions differ between peptides, steroids, and amines.

5. Mechanism of Hormone Action RECEPTORS FOR HORMONE ACTION: Cell Surface Receptors (For peptide hormones like insulin) Intracellular Receptors (For steroid & thyroid hormones) Signal Transduction Pathways: Second messengers ( cAMP , Ca2+ signaling) Gene activation (Steroid hormones regulate gene expression) JUSTIFICATION: Knowing hormone action mechanisms helps in developing drugs that mimic or block natural hormone activity.

6. Mechanism of Hormone Action Hormone Action via Cell Surface Receptors (Peptide Hormones) Peptide hormones (like Insulin, Growth Hormone, TSH ) cannot cross the cell membrane and act through cell surface receptors . Their action involves second messengers like cAMP , Ca²⁺, IP₃, or DAG . PEPTIDE HORMONE ACTION VIA CELL SURFACE RECEPTORS Peptide Hormone (Insulin, GH, TSH) → Binds to Cell Surface Receptor → Activates G-Protein (if GPCR) or Tyrosine Kinase (if RTK) → Activates Second Messenger ( cAMP , Ca²⁺, IP₃) → Cellular Response (Metabolism, Growth, Secretion, etc.)

7. Pathway Example Hormones Second Messenger Effect cAMP Pathway ACTH, TSH, FSH, LH, Glucagon cAMP Activates Protein Kinase A (PKA) → Gene expression/metabolic effects IP₃/DAG Pathway Oxytocin, Vasopressin IP₃, DAG, Ca²⁺ Causes calcium release → Muscle contraction, hormone secretion Tyrosine Kinase Pathway Insulin, GH No second messenger Direct phosphorylation of proteins → Glucose uptake, growth 🔹 Justification : Peptide hormones act quickly via membrane-bound receptors , making them ideal for fast physiological responses (e.g., insulin for glucose uptake).

8. Hormone Action via Intracellular Receptors (Steroid & Thyroid Hormones) Steroid and thyroid hormones are lipid-soluble, meaning they can cross the cell membrane and directly interact with intracellular receptors to regulate gene expression. STEROID/THYROID HORMONE ACTION VIA INTRACELLULAR RECEPTORS Steroid/Thyroid Hormone → Passes through Cell Membrane → Binds to Intracellular Receptor → Hormone-Receptor Complex Enters Nucleus → Binds to DNA (Hormone Response Element) → Activates Gene Transcription → Protein Synthesis → Cellular Effects

9. Pathway Example Hormones Receptor Location Effect Cytoplasmic Receptor Cortisol, Aldosterone Cytoplasm → Nucleus Anti-inflammatory effects (Cortisol), Sodium retention (Aldosterone) Nuclear Receptor Thyroid Hormones (T3, T4) Directly in Nucleus Increases metabolism, protein synthesis 🔹 Justification : These hormones modify gene expression , leading to long-lasting effects (e.g., cortisol reducing inflammation or thyroid hormones boosting metabolism).

10. Signal Transduction Pathways DEFINITION: Signal transduction is the process by which a cell converts an extracellular signal into a functional response. TYPES OF PATHWAYS: Second Messengers cAMP (Cyclic AMP) Ca²⁺ (Calcium Signaling) Inositol triphosphate (IP₃) Gene Activation Steroid hormones diffuse into the cell Bind to intracellular receptors Activate gene transcription

11. 1. EXTRACELLULAR SIGNAL (HORMONE/NEUROTRANSMITTER/GROWTH FACTOR) ⬇ 2. RECEPTOR ACTIVATION (CELL MEMBRANE/CYTOPLASMIC RECEPTORS) ⬇ 3. INTRACELLULAR SIGNAL (SECOND MESSENGERS OR DIRECT GENE ACTIVATION) IF SECOND MESSENGER PATHWAY: Activation of G-protein or kinase → cAMP /Ca²⁺ → Cellular Response IF GENE ACTIVATION PATHWAY: Steroid hormone binds to intracellular receptor → Enters nucleus → Activates transcription ⬇ 4. CELLULAR RESPONSE (ENZYME ACTIVATION, GENE EXPRESSION, METABOLIC CHANGE, ETC.)  

12. JUSTIFICATION UNDERSTANDING HORMONE SIGNALING PATHWAYS HELPS IN DEVELOPING: ✔ Drugs that mimic natural hormones (e.g., insulin injections for diabetes). ✔ Drugs that block hormone actions (e.g., methimazole for hyperthyroidism). ✔ Targeted therapies that act on specific hormone receptors to minimize side effects.  

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