Puberty
• A time of sexual maturation
• Experience physical, hormonal, and sexual changes that allow for reproduction
• Associated with rapid growth and secondary sexual characteristics (e.g., breasts, hair, voice)
• Primary sexual characteristics are those you are born with
o Testes
o Penis
o Labia
o Ovaries
o Vagina
o Cervix
• Puberty in males
o Testosterone is main male sex androgen
o Testosterone made by Leydig cells in between seminiferous tubules in the testes
o LH (released by anterior pituitary in response in GnRH) stimulates production of
testosterone
o Some testosterone is made by adrenal glands – source in females
o Androgens
▪ Steroid hormones that cause masculinizing effects
▪ Mostly made in testes
▪ Testosterone
▪ Dihydrotestosterone (DHT) – most potent
▪ Androstenedione
▪ Bound to plasma proteins – very rarely found free in blood
o Most tissues convert testosterone to DHT as it is more potent
o Excess androgens are released in bile to be excreted in urine
o Males also make oestrogen (Sertoli cells) which helps maturation of spermatozoa
o Testosterone production
▪ During foetal life and a first few month after birth (‘mini puberty’) hCG stimulates
testes to make testosterone
▪ hCG
• Hormone from placenta
• Shares chemical similarities with LH
• Stimulates testes in the same way LH does (same receptors)
▪ After ‘mini puberty’, testosterone is very low until puberty
o Regulation of testosterone release
▪ Testosterone release is proportionate to the amount of LH available
▪ Once released by testes, testosterone inhibits GnRH and gonadotrophins
o Functions of testosterone in foetus
▪ Development of penis, testes, prostate gland, seminal vesicle, epididymis, vas
deferens and ducts (primary sex characteristics)
▪ Testes in abdominal/pelvic region until ‘descent’ occurs in last trimester
▪ Some boys born with undescended testes
• Confers issues with fertility – inside body = warmer temperature that could
damage cells
• In most cases, testosterone spike during mini puberty will descend testes
• If not, artificially increase testosterone levels or surgical descend
o Functions of testosterone at puberty and adulthood
▪ Enlargement of penis and testes
▪ Growth of hair – pubis, face, chest, back
▪ Increase skin thickness
▪ Increase sebaceous secretion – acne
• A time of sexual maturation
• Experience physical, hormonal, and sexual changes that allow for reproduction
• Associated with rapid growth and secondary sexual characteristics (e.g., breasts, hair, voice)
• Primary sexual characteristics are those you are born with
o Testes
o Penis
o Labia
o Ovaries
o Vagina
o Cervix
• Puberty in males
o Testosterone is main male sex androgen
o Testosterone made by Leydig cells in between seminiferous tubules in the testes
o LH (released by anterior pituitary in response in GnRH) stimulates production of
testosterone
o Some testosterone is made by adrenal glands – source in females
o Androgens
▪ Steroid hormones that cause masculinizing effects
▪ Mostly made in testes
▪ Testosterone
▪ Dihydrotestosterone (DHT) – most potent
▪ Androstenedione
▪ Bound to plasma proteins – very rarely found free in blood
o Most tissues convert testosterone to DHT as it is more potent
o Excess androgens are released in bile to be excreted in urine
o Males also make oestrogen (Sertoli cells) which helps maturation of spermatozoa
o Testosterone production
▪ During foetal life and a first few month after birth (‘mini puberty’) hCG stimulates
testes to make testosterone
▪ hCG
• Hormone from placenta
• Shares chemical similarities with LH
• Stimulates testes in the same way LH does (same receptors)
▪ After ‘mini puberty’, testosterone is very low until puberty
o Regulation of testosterone release
▪ Testosterone release is proportionate to the amount of LH available
▪ Once released by testes, testosterone inhibits GnRH and gonadotrophins
o Functions of testosterone in foetus
▪ Development of penis, testes, prostate gland, seminal vesicle, epididymis, vas
deferens and ducts (primary sex characteristics)
▪ Testes in abdominal/pelvic region until ‘descent’ occurs in last trimester
▪ Some boys born with undescended testes
• Confers issues with fertility – inside body = warmer temperature that could
damage cells
• In most cases, testosterone spike during mini puberty will descend testes
• If not, artificially increase testosterone levels or surgical descend
o Functions of testosterone at puberty and adulthood
▪ Enlargement of penis and testes
▪ Growth of hair – pubis, face, chest, back
▪ Increase skin thickness
▪ Increase sebaceous secretion – acne
