Endocrine & Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013

Typical Pathway Typical Signal Transduction Pathway

Endocrine & Cell Communication Part III: Hormonal Communication

Phase 1: Reception = Chemical Messenger The target cell detects the ligand

• Enduring Understanding 3.D Cells communicate by generating, transmitting and receiving chemical • Three major classes of molecules function as • Membrane signals. in vertebrates (ligands) • EK 3D2: Cells communicate with each other through –G- linked receptors Polypeptides (proteins and ) direct contact with other cells or from a distance via – receptors chemical signaling – Amines derived from amino acids – c. Signals released by one cell type can travel long distances – Steroid hormones – Kinase to target cells of another cell types. 1. Endocrine signals are produced by endocrine cells that • release signaling molecules, which are specific and can travel long distances through the blood to reach all parts of –Steroid receptors the body.

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The Process of Communication: Signal-Transduction Pathway Ligands Type of Receptor : G-protein linked

Three stages of the Signal- Transduction Pathway 1. reception LIGAND: 2. transduction a molecule that binds to a larger 3. response molecule

1 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013

Name three types of receptors in the signal Type of Receptor: Ion Channel transduction pathway Transduction

• G-protein-linked receptors • Binding changes the receptor protein. • Ion channel receptors • Can set off a cascade reaction • Intracellular receptors

Action of G-Protein Linked Receptor Response • Set any of a variety of Type of Receptor: cell activities in motion. Intracellular Receptor –Activation of an –Rearrangement of cytoskeleton features –Activation of a specific gene

2 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013

Recap Which Is A Receptor Through Which Ions Would Pass?

EXTRACELLULAR CYTOPLASM FLUID Plasma membrane

1 Reception

Receptor

Signaling molecule

Recap Types of Receptors Which Of These Acts As A Second Messenger?

EXTRACELLULAR CYTOPLASM FLUID Plasma membrane

1 Reception 2 Transduction

Receptor

Relay molecules in a signal transduction pathway +

Signaling molecule

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Water-soluble (hydrophilic) Lipid-soluble (hydrophobic) Recap Which is the receptor? G-Protein? Ligand? Polypeptides Steroids

EXTRACELLULAR CYTOPLASM FLUID Plasma membrane

1 Reception 2 Transduction 3 Response

Receptor 0.8 nm Activation Cortisol of cellular response Amines Relay molecules in a signal transduction pathway

Signaling molecule

Epinephrine Thyroxine

3 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013

Cellular Response Pathways Pathway for Water-Soluble Hormones Pathway for Lipid-Soluble Hormones

• Water- and lipid-soluble hormones differ in their • Binding of a hormone to its receptor initiates a signal • The response to a lipid-soluble hormone is usually a paths through a body transduction pathway leading to responses in the change in gene expression • Water-soluble hormones are secreted by exocytosis, cytoplasm, enzyme activation, or a change in gene • Steroids, , and the hormonal form of travel freely in the bloodstream, and bind to cell- expression vitamin D enter target cells and bind to protein surface receptors receptors in the cytoplasm or nucleus • Lipid-soluble hormones diffuse across cell • Protein-receptor complexes then act as transcription membranes, travel in the bloodstream bound to factors in the nucleus, regulating transcription of transport proteins, and diffuse through the membrane of target cells specific genes

SECRETORY CELL Pathway for Water-Soluble Hormones Pathway for Lipid-Soluble Hormones

Water- Lipid- soluble soluble hormone hormone

VIA BLOOD Transport Signal receptor protein

TARGET CELL Signal receptor

NUCLEUS (a) (b)

SECRETORY CELL Specific Example Example:

Water- Lipid- soluble soluble hormone hormone Notice the presence of the second messenger VIA BLOOD Transport Signal receptor protein

TARGET OR CELL Signal receptor

Cytoplasmic response Gene regulation Cytoplasmic response Gene Click here regulation to view the NUCLEUS animation (a) (b)

4 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013

Compare protein and steroid hormones by completing this T chart

Characteristic Protein Hormone Steroid Hormone

Speed of response Rapid response, cascade Response is slower, gene expression Primary biomolecule Amino acid composition

Method of leaving secretory Exocytosis diffusion cell

Location of receptor Membrane bound Intracellular

Example Testosterone

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Same receptors but different Different receptors Multiple Effects of Hormones intracellular proteins (not shown)

Different cellular Different cellular • The same hormone may have different effects on responses responses Model Steroid Hormone Action target cells that have – Different receptors for the hormone Epinephrine Epinephrine Epinephrine β β α using the Testosterone – Different signal transduction pathways receptor receptor receptor Glycogen Manipulative deposits

Vessel Vessel Glycogen dilates. breaks down constricts. and glucose is released from cell.

(a) Liver cell (b) Skeletal muscle (c) Intestinal blood blood vessel vessel 38

Compare protein and steroid hormones by completing this T chart Multiple Effects of Hormones Did you know…

Characteristic Protein Hormone Steroid Hormone • The hormone epinephrine has multiple effects • One reason that kittens sleep so much is because a growth Speed of response in mediating the body’s response to short-term stress hormone is released only during sleep.

Primary biomolecule The levels of two stress hormones, cortisol and composition • Epinephrine binds to receptors on the plasma • membrane of liver cells epinephrine which suppress the body's , Method of leaving secretory will actually drop after a dose of laughter. cell • This triggers the release of messenger molecules that Location of receptor • Chocolate is associated with the release of , the activate and result in the release of glucose hormone that makes you feel relaxed, calm, and happy. Example into the bloodstream So are hugs.

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5 Endocrine & Cell Communication Part III: Hormonal Communication STUDENT HANDOUTS 2/4/2013

Created by:

Debra Richards Coordinator of Secondary Science Programs Bryan ISD Bryan, TX

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