Male Reproductive Physiology

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Male Reproductive Physiology

• Pituitary-Hypothalamic control of Functions
• Functions of Luteinizing Hormone
• Functions of Folicle-Stimulating Hormone
• Functions of Sertoli Cells
• Functions of Leydig Cells
• Hormonal Production Rates
• Actions of Androgens

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Pituitary-Hypothalamus Control of Male
Reproduction
GnRH
Hypothalamus
LH
FSH
Anterior Pituitary
Testes
Testosterone
Inhibin
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Functions of Luteinizing Hormone in Males

• Stimulation of and Maintenance of Leydig Cells
  (Interstitial Cells)
• Stimulation of Steroidogenesis through cAMP
  mediated reactions
• Stimulation of Fetal, Juvenile and Adult
  Testosterone, Estrogen and DHT production

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Functions of FSH in Males

• Stimulation of Sertoli Cells
• Stimulation of Androgen Binding Proteins
  Formation
• Stimulation of Inhibin Production
• Stimulation of Spermatogenesis

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Embryology of Sex Tissues (1)Male
Female

• Stromal Cells become
• Leydig Cells
• Supporting Cells become
• Sertoli Cells

• Stromal Cells become
• Thecal Cells
• Supporting Cells become
• Granulosa Cells

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Embryology of Sex Tissues (2)Male
Female

• Wolffian Ducts become
• epididymus
• vas deferens
• seminal vessicles
• ejaculatory duct
• Mullerian Ducts (in presence of Mullerian
  Inhibitory Substance MIS Regress)

• Wolffian Ducts Regress
• Mullerian Ducts become
• fallopian tubes
• uterus
• upper 1/3 of vagina

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Embryology of Sex Tissues (3)Male
Female

• Genital tubercle,fold, swelling Urogenital ridge
  Become (In the Presence of dihydrotestosterone)
• Penis
• Scrotum
• Prostate gland

• Genital tubercle,fold, swelling Urogenital ridge
  Become (In the absence of dihydrotestosterone)
• Labia majora
• Labia Minora
• Clitorus
• Lower 2/3 of vagina

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Functions of Leydig Cells

• Production of High Levels of Testosterone (
  5mg/day in adults )
• Direct Production of Estradiol
• Production of Dihydrotestosterone (DHT)
• Production of dehydroepiandrosterone (DHEA) and
  androstenedione
• Production of Progesterone and 17a -prog.

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Functions of Sertoli Cells

• Support Production of Spermatozoa
• Production of Androgen-Binding Protein
  Intratesticularly (TeBG)
• Form Blood-Testes Barrier
• Produce Inhibin
• Produce Seminiferous tubule fluid (bathing
  medium, nutrients, capacitation, motility)

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Hormonal Production Rates

• Testosterone 5 mg/day
• Primary Testicular Androgen
• Estradiol 10-15 mg/day
• Functions in Sperm Production
• Dihydrotestosterone 50-100 mg/day
• 2.5X as powerful as Testosterone
• 17a-Hydroxyprogesterone 1-2 mg/day

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Actions of Androgens in Male 1

• Stimulate Development, Growth and Function of
  Male genitalia
• Stimulate Secondary Sexual Characteristics
• Stimulate male hair growth and pattern
• Sebaceous gland secretion (Acne)
• Bone growth and long bone closure
• Stimulate and maintain male libido (behavior)

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Actions of Androgens in Male 2

• Initiation and Maintenance of Spermatogenesis
• Stim. of Androgen-Binding Globulin Synthesis
  (synergy with FSH)
• Maintains secretions of sex glands

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