Hormonal Regulation of Male Reproduction

on 20.7.06 with 0 comments



  • Brain-Testicular Hormone Axis
hypothalamus gonadotropin releasing hormone (GnRH) ----> anterior pituitary follicle stimulating hormone (FSH) + luteinizing hormone (LH) -----> Blood CIRCULATION -------> testes FSH ----> androgen-binding protein (ABP) ABP ----> concentrating testosterone -----> stimulate spermatogenesis

LH -> testosterone (from interstitial cells)

Negative Feedback testosterone INHIBITS release of GnRH
Inhibin INHIBITS release of FSH





  • Mechanism and Effects of Testosterone
  1. Mechanism of Action
    • testosterone passes through cell membrane (lipid)
    • binds to "hormone receptor" in the nucleus
    • "hormone-receptor complex" binds to acceptor on gene
    • DNA of gene is translated into mRNA
    • mRNA directs protein synthesis in cytoplasm
  2. Synthesis of sex hormones in males
    • Prostate testosterone -> dihydroxytestosterone
    • Some neurons - testosterone -> estrogen
  3. Effects of Targets
  • testes - stimulates spermatogenesis
  • ducts, glands, penis - essential for growth/maintain
  • secondary sex characteristics - develop at puberty
  • pubic, axillary, facial, chest hair growth
  • increase in bone & muscle size
  • sex drive for Males & Females



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Category: Physiology Notes

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