Male Reproductive HormoneBIOCHEMISTRY DEPARTMENT

REPRODUCTIVE HORMONES PRODUCED IN THE MALE BODY

Pituitary gland produces both FSH and LHIn response to: gonadotropin-releasing hormone (GnRH)

Gonadotropin-Releasing Hormonesynthesized in hypothalamus:- carried to pituitary by hypophyseal portal systemsecreted in pulses:at 6090 minute intervalsControl rates of secretion of:FSH and LH testosterone (released in response to LH)

FSH stimulates spermatogenesis (production of sperm) LH stimulates the secretion of testosterone

REPRODUCTIVE HORMONES PRODUCED IN THE MALE BODY

Luteinizing HormoneTargets interstitial cells of testesInduces secretion of: testosteroneother androgens

FSH and TestosteroneTarget cells of seminiferous tubulesThese cells:promote spermatogenesis and spermiogenesissecrete androgen-binding protein (ABP)

Negative FeedbackSpermatogenesis is regulated by: - GnRH, FSH, and inhibinAs spermatogenesis accelerates:inhibin secretion increases Inhibin inhibits FSH production:Suppresses secretion of GnRH at hypothalamus

Inhibin and FSHElevated FSH levels:increase inhibin productionuntil FSH returns to normalIf FSH declines:inhibin production fallsFSH production increases

TESTES Testosterone Estrogen Inhibin

SYNTHESIS

Mechanism of action

Functions of TestosteroneStimulates spermatogenesis: promoting functional maturation of spermatozoaAffects CNS function: libido (sexual drive) and related behaviorsEst. male secondary sex characteristics:distribution of facial hairincreased muscle mass and body sizecharacteristic adipose tissue depositsMaintains accessory glands and organs

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