Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ GENERAL PRINCIPLES OF ENDOCRINOLOGY ++ A hormone is a chemical produced by the body that has a specific regulatory effect on a target cell or organ. Chemical signaling can occur in three modes (Figure 8-1). Endocrine: The hormone is carried a large distance via the blood. Paracrine: The hormone only diffuses in local extracellular fluid. Autocrine: The hormone acts at receptors on the cell that secreted it (e.g., growth factors made by cancer cells). The seven classical endocrine glands are the pituitary, adrenal, thyroid, parathyroid, pancreas, testis, and ovary (Table 8-1). Other organs also secrete hormones (e.g., hypothalamus, heart, kidney, gastrointestinal tract, liver, adipose tissue, bone). Endocrine diseases may be caused by excess or deficiency of a hormone or by defects in hormone receptors or downstream intracellular signaling. Certain neoplasms (e.g., small cell lung cancer) may secrete hormones, causing paraneoplastic syndromes. ++ Figure 8-1 Modes of intercellular communication. Graphic Jump LocationView Full Size||Download Slide (.ppt)++Table Graphic Jump LocationTable 8-1Summary of Hormones Produced by the Major Endocrine OrgansView Table||Download (.pdf) Table 8-1 Summary of Hormones Produced by the Major Endocrine Organs Endocrine Gland Hormone(s) Produced Chemical Structure Overview: Major Function(s) Hypothalamus Corticotropin-releasing hormone (CRH) Peptide Stimulates adrenocorticotropic hormone (ACTH) Growth hormone-releasing hormone (GHRH) Peptide Stimulates growth hormone (GH) release Growth hormone inhibitory hormone (GHIH; also known as somatostatin) Peptide Inhibits GH release Gonadotropin-releasing hormone (GnRH) Peptide Stimulates luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release Prolactin-inhibiting factor (PIF; also known as dopamine) Peptide Inhibits prolactin release Thyrotropin-releasing hormone (TRH) Peptide Stimulates thyroid-stimulating hormone (TSH) and prolactin release Anterior pituitary ACTH Peptide Trophic to adrenal cortex Stimulates synthesis and secretion of cortisol, aldosterone, and androgens FSH Peptide Promotes sperm maturation via Sertoli cells in testes Stimulates ovarian follicle development GH Peptide Acute metabolic effects oppose insulin Chronic growth-promoting effect via insulin-like growth factor 1 (IGF-1) LH Peptide Stimulates Leydig cells of testes to secrete testosterone LH surge important for ovulation and formation of corpus luteum Prolactin Peptide Required in lactation for mammary growth, initiation of milk secretion, and maintenance of milk production TSH Peptide Stimulates synthesis and secretion of thyroid hormones Posterior pituitary Antidiuretic hormone (ADH) (also called arginine vasopressin, or AVP) Peptide Increases water retention at kidney Vasoconstricts arterioles Oxytocin Peptide Stimulates uterine contractions during labor Milk ejection in lactation Thyroid Triiodothyronine (T3) and thyroxine (T4) Amine Increase metabolic rate Required for normal growth and development Adrenal cortex Aldosterone Steroid Decreases urinary Na+ excretion Increases urinary K+ and H+ excretion Cortisol Steroid Released in response to stress Multiple metabolic actions Adrenal medulla Epinephrine and norepinephrine Amine Produces effects similar to actions of the sympathetic nervous system Pancreas Insulin (β cell) Peptide Promotes storage of glucose as glycogen in liver and muscle Promotes uptake of glucose and storage as triglyceride in adipose tissue and liver Glucagon (α ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.