Flashcard for reproductive hormone
### **Estrogen**
1. **Synthesis Site**
- Mainly synthesized in the ovaries and liver.
2. **Metabolism**
- Converted to glucuronide and sulfate conjugates in the liver.
- Excreted in urine; also undergoes enterohepatic circulation.
3. **Secretion Pathway**
- Secreted in bile and reabsorbed into the bloodstream.
4. **Mode of Action (MOA) During Puberty**
- Female secondary sex characteristics development.
- Proliferation of mammary ducts and reproductive tract maturation.
5. **Systemic Effects**
- Modulates bone density, cardiovascular system, and mood.
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### **Progesterone**
6. **Indicates Ovulation**
- Surge follows LH peak; secreted by corpus luteum and placenta.
7. **Metabolism**
- Converted to pregnanediol in the liver; excreted in urine as glucuronic acid conjugates.
8. **Target Organs**
- Uterus: Induces secretory phase in the endometrium.
- Cervix: Thickens mucus, inhibiting ferning caused by estrogen.
9. **Role in Pregnancy**
- Anti-estrogenic effect on myometrium, reducing oxytocin sensitivity.
10. **Effects on Breast Tissue**
- Promotes growth of lobules and alveoli.
11. **Thermogenic Effect**
- Causes a rise in basal body temperature at ovulation.
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### **Testosterone**
12. **Synthesis Site**
- Synthesized in Leydig cells and from adrenal cortex androstenedione.
13. **Plasma Binding**
- 98% bound to protein (65% to gonadal steroid-binding globulin, 33% to albumin).
14. **Metabolism**
- Converted to estradiol or androsterone; excreted in urine.
15. **Effects During Development**
- Maturation of Wolffian ducts (internal male genitalia).
16. **DHT-Specific Effects**
- External genitalia enlargement, facial hair growth, and acne.
17. **Anabolic Effects**
- Increases muscle mass, sodium retention, and kidney size.
18. **Spermatogenesis Role**
- Testosterone concentration maintained by ABP from Sertoli cells.
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### **Inhibins and Activins**
19. **Inhibins**
- Inhibit FSH secretion via direct pituitary action.
- Inhibin B regulates FSH in adults; secreted by Sertoli and granulosa cells.
20. **Activins**
- Stimulate FSH secretion; exact role not fully understood.
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### **Relaxin**
21. **Production Sites**
- Corpus luteum, uterus, placenta, mammary glands in women; prostate gland in men.
22. **Pregnancy Effects**
- Relaxes pubic symphysis, softens cervix, and inhibits uterine contractions.
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### **Estrogen Receptors**
23. **Types**
- ERα (chromosome 6) and ERβ (chromosome 14).
24. **Selective Estrogen Receptor Modulators (SERMs)**
- Tamoxifen and others mimic estrogen selectively for therapeutic use.
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### **Progesterone Receptors**
25. **Types**
- PRA and PRB; bound to heat shock protein until activated by progesterone.
26. **Mechanism of Action**
- Receptor activation induces mRNA synthesis and cellular changes.
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### **Testosterone and DHT Mechanism**
27. **Receptor Binding**
- Testosterone and DHT bind the same intracellular receptor; DHT has higher affinity.
28. **Gene Activation**
- Steroid-receptor complex facilitates gene transcription.
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### **Abnormalities of Function**
29. **Testicular Estrogen Production**
- Occurs via aromatization in Leydig and Sertoli cells.
30. **Testosterone Regulation**
- Systemic testosterone inhibits LH, reducing spermatogenesis