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Steroid Hormones

Steroid Hormones. Estrogen & Progesterone. The Female Body. Estrogen Development of secondary sex characteristics Growth of uterus during puberty Initial growth of endometrium during menstrual cycle. Progesterone Development of breasts during puberty

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Steroid Hormones

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  1. Steroid Hormones Estrogen & Progesterone

  2. The Female Body Estrogen Development of secondary sex characteristics Growth of uterus during puberty Initial growth of endometrium during menstrual cycle Progesterone Development of breasts during puberty Growth of endometrium during menstrual cycle Inhibition of uterine contractions during pregnancy

  3. The Ovarian Cycle Follicular Stage -GnRH induces release of LH & FSH -Follicular growth & secretion of estradiol Ovulation Stage -Follicle bursts releasing mature ovum -Broken follicle develops into corpus luteum

  4. The Ovarian Cycle Luteal Stage -Corpus luteum secretes estrogen and progesterone -Estrogen & progesterone decrease GnRH, LH & FSH levels inhibiting further ovulation -No fertilization in 25 days leads to the endometrial deterioration Fertilization -Zygote produces an LH-like hormone so the corpus luteum can secrete estrogen & progestrone causing the endometrium to stay in place

  5. Endogenous Estrogens

  6. Biosynthesis of Estrogen and Progesterone

  7. Aromatase Inhibitors Aromatase - Cytochrome P-450 complex that catalyzes the conversion of androstenedione to estrone and testtosterone to estradiol Steroidal Aromatase Inhibitors - Irreversible - Act as natural substrate of aromatose

  8. Aromatase Inhibitors Non-Steroidal Aromatase Inhibitors - Reversible - Enough estrogen displaces these - Anastrozole (Shown)

  9. Estrogen Receptor Types ER-α - Found in uterus, vagina, breasts, and kidneys - 595 amino acid residues ER-β - Found in ovaries, lungs, and bladder - 485 amino acid residues

  10. Estrogen Receptor Domains A/B Domain - Contains AF-1 C Domain - DNA binding domain - Contains 2 Zinc fingers D Domain - Translocates complex into nucleus E Domain - Hormone / Ligand binding region - Contains AF-2 - Where ER-α and ER-β differ

  11. Estrogen Receptor Action Agonists - Cause helix 12 to sit snuggly over domain D - AF-2 is capable of achieving transcription Antagonists - Rearrange formation of helix 12 - AF-2 is incapable of transcription

  12. Estrogen Antagonists - Help treat and prevent estrogen dependent breast cancer • Characteristics of a good antagonist • - Substitution at 7-α with long alkyl • chain • - Substitution at 11-β with long, non • polar substituents Fulvestrant • Characteristics of a bad antagonist • Substitution at 7-α with bulky chains, alcohol, carboxylic acid, aryl, or ester groups • Substitution at 11-β with polar groups

  13. Selective Estrogen Receptor Modulators Tamoxifen - Antagonist to breast tissue - Agonist to endometrium, liver, and bone tissue Raloxifen - Antagonist to breast and endometrial tissue - Agonist to bone tissue

  14. Progestins Natural Progesterone Synthetic Progestins - Deletion of methyl group at carbon-13 - Addition of double bond between carbon 6 and 7 - Added substituent at carbon-12

  15. Oral Contraceptive Agents • Believed to suppress the production of LH and FSH so that ovulation does not occur • Monophasic combinations such as Yasmin, contain the same amount of drug in each tablet ( 3 mg of drosperinone and 30 mg of ethinyl estradiol )

  16. Oral Contraceptive Agents • Biphasic and triphasic combinations mimic the variation of estrogen and progesterone levels naturally created by the body • Ortho-Tri-Cyclen • Tablet of 0.18 mg of norgestimate and 35 mg of ethinyl estradiol for 7 days • Tablet of 0.215 mg of norgestrimate and 35 mg of ethinyl estradiol for 7 days • Tablet of 0.25 mg of norgestrimate and 35 mg of ethinyl estradiol for 7 days

  17. Abortifacient : Mifepristone • Progesterone receptor antagonist of the uterus • Promotes shedding of endometrium, softening of the cervix, and uterine contractions leading to spontaneous abortion • Often used in conjunction with misoprostol prostoglandin

  18. Conclusion • The natural steroid hormones estrogen and progesterone are produced in large quantities by our bodies. • Synthesized versions are important to the medical community because they provide hope for breast cancer patients, allow for contraception, and can be used for abortion.

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