steroid hormones
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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 - PowerPoint PPT PresentationTRANSCRIPT
STEROID HORMONES
J E N N A B O O T H , C H R I S T A B E V E R I D G E , A B I G A I L R U T H S , A N D
P A U L A C O O K
13.10 PHYSIOLOGICAL ROLES OF STEROID HORMONES
• 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
PROGESTERONE Starting compound for Sex hormonesAdrenocorticoid
ADRENOCORTICOID HORMONESProducts of adrenal glandsTwo groupsMineralocorticoids
Regulate the concentrations of ionsGlucocorticoids
Control carbohydrate metabolism
Corticoid-indicates that the site of the secretion is cortrex of the gland
MINERALOCORTICOIDS
Aldesterone is the most importantIncreased secretion Enhances the reabsorptionIncreases loss of KControls tissue swelling
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
SEX HORMONESMale hormone-testosteronePromotes 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
CONTINUED…LH (luteinizing Hormone)is anotherTriggers ovulationThe ovulation increases progesterone level
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
13.11 BILE SALTS
Products of cholesterol in oxidationCholesterol Trihydroxy derivativeEnd of aliphatic chain Carboxylic acidForms amide bond with amino acid (glycine or taurine)
Taurine has developed an importance in sports drinksEx) Red Bull contains sugars, caffeine and B vitamins as well as taurine
Bile salts are powerful detergentsOne end is hydrophilicBecause of negative charge
The rest is hydrophobicThey can disperse dietary lipids in the
small intestine into fine emulsionsFacilitates digestionSimilar to action of soap on dirt
Can also remove excess cholesterol in 2 ways
Breakdown cholesterol by themselvesCholesterol is thus eliminated with bile salts
Solubilize deposited cholesterol in the form of bile salt- cholesterol particles
13.12- PROSTAGLANDINS, THROMBOXANES, & LEUKOTRIENES
PROSTAGLANDINSProstaglandins: group of fatty-acid-like
substancesSeminal gland secretes 0.1 mg of prostaglandin
per daySmall amounts present throughout body of both sexesSynthesized in body from arachidonic acid by a
ring closure at carbons 8 & 12Enzyme catalyzing this reaction is cyclooxygenase (COX)
Product known as PGG2
PROSTAGLANDINS CONT’DProstaglandin E group (PGE) has a
carbonyl group at carbon 9Subscript 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*
PROSTAGLANDINS CONT’DCOX enzyme has 2 forms in body: COX-1 and
COX-2COX-1: catalyzes normal physiological production of prostaglandinsLowers 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*
Thromboxanes = another class of archidonic acid derivatives
Synthesis also includes a ring closureDerived from PGH2, but ring is a cyclic acetal
BLOOD CLOTS Thromboxane induces platelet
aggregationWhen blood vessel is ruptured, first line of defense is the platelets circulating in the blood. Forms an incipient clotThromboxane A2 causes other platelets to clump, increases clot
BLOOD THINNERSAspirin and similar anti-inflammatory
agents inhibit the COX enzymeAs 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
PGH2
Thrombaxane A2
Variety of NSAIDs can inhibit COZ enzymes
Ibuprofin & indometacin (powerful painkillers) block aspirin’s effect
Eliminate anticlotting benefitsUse together is NOT recommendedAcetaminophen & diclophenac DON’T
interfere, can be taken together
LEUKOTRIENSAlso act to mediate hormonal
responsesDerived (like prostaglandins) from arachidonic acid by an oxidative mechanism
No ring closure
Leukotrienes occur mainly in white bloodcells
Also found in other body tissuesProduce long-lasting muscle
contractions, especially in lungsCan cause asthma-like attacksProstaglandins and leukotrines cause
inflammation and fever
To counteract the effects of leukotrienes:Inhibit their uptake by Leukotriene
receptors (LTRs) in the bodyZafirlukast and Zileuton
commercial drugs used to treat and control athsma