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Steroid Hormones

Steroid Hormones. 13.10-13.12 Katlyn Raker and Amanda Carl. Physiological roles. Cholesterol is the starting material for the synthesis of steroid hormones Progesterone Compound for Sex hormones Adrenocorticoid hormones. Adrenocoticoid hormones. Products of adrenal glands

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Steroid Hormones

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  1. Steroid Hormones 13.10-13.12 KatlynRaker and Amanda Carl

  2. Physiological roles • Cholesterol is the starting material for the synthesis of steroid hormones • Progesterone • Compound for • Sex hormones • Adrenocorticoid hormones

  3. Adrenocoticoid hormones • Products of adrenal glands • Adjacent to the renal (kidney) • Classified into 2 groups • Mineralocorticoid • Regulate concentrations of ions (Na and K) • Glucocorticoids • Control carbohydrate metabolism

  4. Corticoid • Indicates the site of the secretion is the cortex (outer part of gland) • Aldosterone • Most important mineralocorticoids • Increased secretion of aldosterone enhances the reabsorption of Na and Cl ions in the kidney tubules and increases the loss of K • Controls tissue swelling

  5. Cortisol • Major glucocorticoid • Increase glucose and glycogen concentration in the body • Fatty acids from fat storage cells and amino acids from body proteins • Transported to liver and under the influence of cortisol it manufactures glucose and glycogen • Cortisol and cortisone (Ketone derivative) • Anti-flammatory effects

  6. Sex hormones • Male- Testosterone • Promotes growth of genital organs • Synthesized in testes from cholesterol • Female- Estradiol • Synthesized from corresponding male hormone by aromatization of the A ring

  7. Along with progesterone it regulates the cyclic changes in the uterus and ovaries (Period) • Level of estradiol rises uterus thickens

  8. Luteinizing hormone (LH) • Triggers ovulation • Estradiol and progesterone • Promote further preparation of the uterine lining to receive the fertilized ovum • No fertilization means the progesterone production stops and estradiol production decreases

  9. Progesterone is essential for the implantation of the fertilized ovum • Blocking its action leads to a miscarriage • The levels of sex hormones in the blood stream during a period (menstration) prevent pregnancy • Development of an ovarian follicle • Proliferative phase- The endometrium (lining of the uterus) thickens

  10. Secretory phase- the lining continues to thicken and the glands secrete a glycogen rich nutritive material in preparation to receive an embryo • If there is no embryo the new outer layers disintegrate which causes blood flow

  11. Mifepristone (RU486) • Blocks action of progesterone by binding to the same receptor sites • Ovum is aborted since the progesterone cannot reach the receptor molecule • If pregnancy is established Mifepristone can be taken no less than 72 hours after intercourse for 49 days of gestation

  12. Facts • Mifepristone is a supplement to surgical abortions • The morning after pill is not an abortion pill • Since estradiol and progesterone regulate the growth of breasts, Mifepristone has been noted to be effective against breast cancer

  13. Bile salts • Oxidation products of cholesterol • Powerful detergents • One end is negatively charged so its strongly hydrophilic • The rest is largely hydrophobic • Disperse dietary lipids in the small intestine into fine emulsions which facilitates digestion • Similar to soap and dirt

  14. Prostaglandis • Group of fatty acid like substances • Discovered by Kurzruk and Leib in the 1930’s • Name came from Ulf von Euler of Sweden who isolated the two compounds from semen, thinking they came from the prostate gland • Mature male= secretes .1mg per day

  15. Both sexes= a little is present throughout the body • Synthesized in the body from arachidonic acid by a ring closure at carbons 8 and 12 • Catalyst= COX (cyclooxygenase) • Aspirin inhibits this enzyme

  16. Thromboxanes • Includes a ring closure • Another class of a arachidonic acid derivative • Induces platelet aggregation • Increases size of blood clot • Aspirin impairs the clotting from thromboxane

  17. Leukotrienes (LTR’s) • Causes inflammation and fever • Acts to mediate hormonal responses • No ring closure • Mostly occur in white blood cells • Produce long lasting muscle contractions especially in the lungs • Can cause asthma like attacks • You would take zafirlukast (Accolate) to help chronic asthma because it acts against the inflammation

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