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Steroid Hormones

Steroid Hormones. Cholesterol Starting material. Steroid Sex Hormones. Androgens: male sex hormones synthesized in the testes responsible for the development of male secondary sex characteristics. Steroid Hormones. Among the synthetic anabolic steroids are:.

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Steroid Hormones

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  1. Steroid Hormones Cholesterol Starting material

  2. Steroid Sex Hormones • Androgens: male sex hormones • synthesized in the testes • responsible for the development of male secondary sex characteristics

  3. Steroid Hormones • Among the synthetic anabolic steroids are: Prohormones, see p.515 Chemical Connections 20G Why are these hormones of interest? Do steroids really work? i.e. improve muscle mass and performance? . . .

  4. A resounding Yes . . .

  5. Steroid Sex Hormones • Estrogens: female sex hormones • synthesized in the ovaries from progesterone  testosterone . . . (aromatization) estradiol • responsible for the development of female secondary sex characteristics and control of the menstrual cycle

  6. Steroid Sex Hormones A woman's monthly cycle w/o the pill (Blue and Red solid lines) • Progesterone-like analogs are used in oral contraceptives: they Make the body think it is Pregnant at all times. . .  preventing folicle stimulation and ovulation. . . A woman's monthly cycle on the pill (Blue and Red dashed lines)

  7. Steady stream of Progesterone required for implantation and development of oocyte Other pills block Progesterone all together. . .e.g. RU- 486 Progesterone Prevents egg from staying implanted . . Gets released. . .

  8. Steroid Hormones • Adrenocorticoid hormones • synthesized in the adrenal cortex. • regulate metabolism of carbohydrates. • decrease inflammation. • involved in the reaction to stress.

  9. Bile Salts • Bile salts, the oxidation products of cholesterol. • synthesized in the liver, stored in the gallbladder, and secreted into the intestine where they emulsify dietary fats and aid in their absorption and digestion

  10. Other Classes Lipids: - Prostaglandins- Thromboxanes - Leukotrienes • Prostaglandins: a family of compounds that have the 20-carbon skeleton of prostanoic acid.

  11. Prostaglandins • Not stored in tissues - synthesized from membrane-bound 20-carbon polyunsaturated fatty acids in response to specific physiological triggers. • One such polyunsaturated fatty acid is arachidonic acid.

  12. Prostaglandins

  13. COX Enzymes • The COX (cyclooxygenase) enzyme occurs in two forms: • 1. COX-1 catalyzes the normal physiological production of prostaglandins. • 2. COX-2 is responsible for the production of prostaglandins in inflammation. • Tissue is injured or damaged, special inflammatory cells invade the injured tissue and interact with resident cells, e.g. smooth muscle cells or skin. • This interaction activates COX-2 and prostaglandins are synthesized. Aspirin helps relieve this anti-inflammatory response By inhibiting the production of prostaglandins . . .

  14. Thromboxanes • Thromboxanes are also derived from arachidonic acid. • Thromboxane A2 induces platelet aggregation and vasoconstriction. • Aspirin and other NSAIDs inhibit the synthesis of thromboxanes by inhibiting the COX enzyme.

  15. Challenge Questions How Does Aspirin prevent strokes caused by blood clots in the brain? NOTE: Doctors recommend 81mg/ day for people at risk for Heart Attack or stroke. . .

  16. Leukotrienes • Leukotrienes are also synthesized from arachidonic acid. • They occur mainly in leukocytes. • They produce muscle contractions, especially in the lungs and thereby can cause asthma-like attacks. • In this regard, they are 100 times more potent than histamine. • Several recently-developed anti-asthma drugs inhibit the synthesis of leukotrienes.

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