Higher life forms must have molecular mechanisms for detecting environmental information as well as mechanisms that allow for communication at the cell and tissue levels. Sensory systems detect and integrate physical and chemical information from the environment and pass this information along by the process of neurotransmission. Control and coordination of processes at the cell and tissue levels are achieved not only by neurotransmission but also by chemical signals in the form of hormones that are secreted by one set of cells to direct the activity of other cells. | Chapter 34 The Reception and Transmission of Extracellular Information to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline Hormones and Signal Transduction Pathways Signal-Transducing Receptors Transmit the Hormonal Message Intracellular Second Messengers GTP-Binding Proteins” The Hormonal Missing Link The 7-TMS receptor Outline Specific Phospholipases Calcium as a Second Messenger Protein Kinase C The Single TMS-receptor Protein Modules Steroid Hormones SPECIAL FOCUS: Neurotransmission and Sensory Systems Classes of Hormones (There may be others, but we doubt it.) Steroid Hormones - derived from cholesterol- regulate metabolism, salt/water balances, inflammation, sexual function Amino Acid Derived Hormones - epinephrine, regulate smooth muscle , blood pressure, cardiac rate, lipolysis, glycogenolysis Peptide Hormones - regulate many processes in all tissues - including release of other hormones Signal-Transducing Receptors Transmit Hormone Message Non-steroid hormones bind to plasma membrane and activate a signal-transduction pathway inside the cell Steroid hormones may either bind to the plasma membrane or enter the cell and travel to the nucleus Types of Receptors Three that we know of. 7-transmembrane segment receptors extracellular site for hormone (ligand) intracellular site for GTP-binding protein Single-transmembrane segment receptors extracellular site for hormone (ligand) intracellular catalytic domain - either a tyrosine kinase or guanylyl cyclase Oligomeric ion channels Second Messengers Many and there may be more! The hormone is the "first messenger" The second messenger - Ca2+, cAMP or other - is released when the hormone binds to its (extracellular) . | Chapter 34 The Reception and Transmission of Extracellular Information to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline Hormones and Signal Transduction Pathways Signal-Transducing Receptors Transmit the Hormonal Message Intracellular Second Messengers GTP-Binding Proteins” The Hormonal Missing Link The 7-TMS receptor Outline Specific Phospholipases Calcium as a Second Messenger Protein Kinase C The Single TMS-receptor Protein Modules Steroid Hormones SPECIAL FOCUS: Neurotransmission and Sensory Systems Classes of Hormones (There may be others, but we doubt it.) Steroid Hormones - derived from cholesterol- regulate metabolism, salt/water balances, inflammation, sexual function Amino Acid Derived
