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Steroid Hormones

Steroid Hormones. Jenna Booth, Christa Beveridge , Abigail Ruths , and Paula Cook. 13.10 Physiological Roles of Steroid Hormones. Cholesterol is the starting material for the synthesis of steroid hormones

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Steroid Hormones

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  1. Steroid Hormones Jenna Booth, Christa Beveridge, Abigail Ruths, and Paula Cook

  2. 13.10 Physiological Roles of Steroid Hormones

  3. Cholesterol is the starting material for the synthesis of steroid hormones • The alphatic side chain on the D ring is shortened with the removal of a six- carbon unit • Results in progesterone

  4. Progesterone • Starting compound for • Sex hormones • Adrenocorticoid

  5. Adrenocorticoid Hormones • Products of adrenal glands • Two groups • Mineralocorticoids • Regulate the concentrations of ions • Glucocorticoids • Control carbohydrate metabolism Corticoid-indicates that the site of the secretion is cortrex of the gland

  6. Mineralocorticoids • Aldesterone is the most important • Increased secretion • Enhances the reabsorption • Increases loss of K • Controls tissue swelling

  7. Glucorticoids • Cortisol is major glucocorticoids • Job is to increase the glucose and glycogen in the body • Fatty acid from fat storage cells and amino acids from body protiens to the liver • Antiinflamitory • Used to treat inflamatory diseases

  8. Sex hormones • Male hormone-testosterone • Promotes normal growth of the male genital organ is synthesized in the testes from cholesterol Female sex hormones - most important is estradiol -regulates mensral cycle -level of estradiol increase when cycle begins

  9. Continued… • LH (luteinizing Hormone)is another • Triggers ovulation • The ovulation increases progesterone level

  10. Mifepristone blocks the action of progesterone • This is done by binding to the same receptor • Completely different approach is the morning pill • It has a progesertone-like compound called levonogestestrel

  11. 13.11 Bile Salts

  12. Products of cholesterol in oxidation • Cholesterol Trihydroxy derivative • End of aliphatic chain Carboxylic acid • Forms amide bond with amino acid (glycine or taurine) • Taurine has developed an importance in sports drinks • Ex) Red Bull contains sugars, caffeine and B vitamins as well as taurine

  13. Bile salts are powerful detergents • One end is hydrophilic • Because of negative charge • The rest is hydrophobic • They can disperse dietary lipids in the small intestine into fine emulsions • Facilitates digestion • Similar to action of soap on dirt

  14. Can also remove excess cholesterol in 2 ways • Breakdown cholesterol by themselves • Cholesterol is thus eliminated with bile salts • Solubilize deposited cholesterol in the form of bile salt- cholesterol particles

  15. 13.12- Prostaglandins, Thromboxanes, & Leukotrienes

  16. Prostaglandins • Prostaglandins: group of fatty-acid-like substances • Seminal gland secretes 0.1 mg of prostaglandin per day • Small amounts present throughout body of both sexes • Synthesized in body from arachidonicacid by a ring closure at carbons 8 & 12 • Enzyme catalyzing this reaction is cyclooxygenase (COX) • Product known as PGG2

  17. Prostaglandins cont’d • Prostaglandin E group (PGE) has a carbonyl group at carbon 9 • Subscript indicates # of double bonds in hydrocarbon chain • Prostaglandin F group (PGF) has two hydroxyl groups on the ring at carbons 9 & 11 • Other prostaglandins (PGAs and PGBs) are derived from PGE • *diagram on page 294*

  18. Prostaglandins cont’d • COX enzyme has 2 forms in body: COX-1 and COX-2 • COX-1: catalyzes normal physiological production of prostaglandins • Lowers blood pressure, treats asthma, decongestant • COX-2: responsible for production of prostaglandins in inflammation • Helps to produce new tissue in injuries such as: heart attack, rheumatic arthritis, & ulcerative colitis • *aspirin inhibits both COX enzymes*

  19. Thromboxanes = another class of archidonic acid derivatives • Synthesis also includes a ring closure • Derived from PGH2, but ring is a cyclic acetal

  20. Blood Clots • Thromboxane induces platelet aggregation • When blood vessel is ruptured, first line of defense is the platelets circulating in the blood. Forms an incipient clot • Thromboxane A2 causes other platelets to clump, increases clot

  21. Blood Thinners • Aspirin and similar anti-inflammatory agents inhibit the COX enzyme • As a result, PGH2 and thromboxane synthesis is inhibited, and blood clotting is impaired • Many physicians recommend 81 mg aspirin a day for people at risk of heart attack or stroke • Forbid patients to use it before planned surgery  aspirin and other NSAIDs may cause excessive bleeding

  22. PGH2 Thrombaxane A2

  23. Variety of NSAIDs can inhibit COZ enzymes • Ibuprofin & indometacin (powerful painkillers) block aspirin’s effect • Eliminate anticlotting benefits • Use together is NOT recommended • Acetaminophen & diclophenac DON’T interfere, can be taken together

  24. Leukotriens • Also act to mediate hormonal responses • Derived (like prostaglandins) from arachidonic acid by an oxidative mechanism • No ring closure

  25. Leukotrienes occur mainly in white bloodcells • Also found in other body tissues • Produce long-lasting muscle contractions, especially in lungs • Can cause asthma-like attacks • Prostaglandins and leukotrines cause inflammation and fever

  26. To counteract the effects of leukotrienes: • Inhibit their uptake by Leukotriene receptors (LTRs) in the body • Zafirlukast and Zileuton commercial drugs used to treat and control athsma

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