1. Chapter 4 Extracellular signals: Hormones, cytokines and growth factors

2. Objectives Understand the general role of Hormones, Cytokines, Growth Factors and Neurotransmitters Learn the abbreviations for the general molecules in each class Know one example of a function for each group of signals

3. Hormones Small water soluble molecules – Cannot cross plasma membrane – Must target cellular receptor – Examples Histamine Epinephrine

4. Hormones Peptide Hormones – Water soluble – Stored in vacuoles – Pro-peptides – Examples Insulin Glucagon LH (luteinizing hormone) FSH (follicle stimulating hormone)

5. Hormones Lipophilic molecules (extracellular) – Still need a receptor – Prostaglandins Synthesized from arachidonic acid – Usually have to do with inflammation

6. Hormones Lipophilic molecules (intracellular) – Receptors are on the inside of the cell – Steroid hormones – Examples Testosterone Progesterone Thyroxine

7. Hormones Plant hormones (for Joe!!) – All extracellular signals – Auxin Young leaves and seeds Very diverse effects – Cytokinins Developing seeds – Gibberellins Young shoots and seeds Flowering and germination – Abscisic acid Roots and mature leaves Stromal closure – Ethylene Gas Fruit ripening

8. Cytokines Very large family of peptides Range in size from 10-70 kDa Name of GroupExamplesNotes InterferonsIFN- α IFN- β IFN- γ Viral infection response InterleukinsIL-1 to IL-35 Some with more than one isoform Cell growth and differentiation Tumor necrosis factors TNF α TNF β TGF β Inflammatory response ChemokinesMIP-1 α NAP-2 RANTES Leukocyte location signals Colony stimulating factors M-CSF G-CSF GM-CSF Development of bone marrow

9. Cytokines Interleukins – 37 family members – IL-x – Many different sizes – Many different receptors – Many different functions Immune response and maturation Can activate themselves or nearby cells

10. Cytokines Interferons – Type I IFN- α, INF- β, IFN-Ω – Type II INF-γ – Anti-tumor properties? Tumor necrosis factors – TNF-α and TNF-β Works closely with IFN and causes necrosis of tumors (hence the name!!)

11. Growth Factors Platelet-derived growth factors (PDGF) – Induces cell migration & proliferation Fibrosis and arteriosclerosis Epidermal growth factor (EGF) – Various functions Fibroblast growth factor (FGF) – Cell proliferation, migration and motility Proto-oncogenes?

12. Neurotransmitters Stored in vesicles, released upon Ca 2+ stimulation Small Molecules – Acetylcholine, GABA, dopamine, γ-aminobutyric acid – Glycine, glutamate, ATP and adenosine Neuropeptides – Substance P, Endorphin, vasopressin