25.10.19
L4 – Reproductive endocrinology
Keywords:
Gametogenesis (formation of gametes), spermiogenesis (formation of sperm), oogenesis (formation
of eggs), dimorphism (physical difference between male and female), dysgenesis (abnormal organ
development) androgen (group of hormones that produce male traits)
Lecture:
Sex determination THEN sex differentiation
Depends on if spermatozoon contains X or Y chromosome
Week 7 differentiates males and females (via sex-determining region of Y (SRY and SOX9
proteins formed))
Undifferentiated genitalia contain Müllerian ducts and Wolffian ducts
o When differentiated in females Wolffian is lost
o When differentiated in males Müllerian is lost
Not required ducts eg female ducts in a male regress caused by AMH hormone and high
androgen levels (opposite in females)
MALE REPODUCTIVE
Seminal tubules = highly coiled tubules drain into rete
testis
o Fluid in lumen of tubules
o Interstitial tissue have Sertoli cells (nurse sperm
cells)
o Germ cells end up as spermatozoon
Then drain into epididymis and sperm joined to urethra via
vas deferens
o Outside tubule = Leydig cells
Hypothalamic-pit reg of LH and FSH (gonadotrophins)
o Synthesized by gonadotrophs in ant pit
o Stimulated by gonadotrophin releasing hormone
(GnRH)
o LH and FSH work on
LH → Leydig cells = testosterone look more
active
Testosterone also suppress GnRH
secretion by suppressing
hypothalamus
Testosterone inhibits LH/FSH via
inhib alt pit
FSH → Sertoli cells = inhibin
Made of two proteins
Inhibits FSH from pit
Male hormones (androgens) required to make sperm
o All bind to androgen-binding protein
o Main androgen = testosterone
Metabolized into dihydrotestosterone (potent)
L4 – Reproductive endocrinology
Keywords:
Gametogenesis (formation of gametes), spermiogenesis (formation of sperm), oogenesis (formation
of eggs), dimorphism (physical difference between male and female), dysgenesis (abnormal organ
development) androgen (group of hormones that produce male traits)
Lecture:
Sex determination THEN sex differentiation
Depends on if spermatozoon contains X or Y chromosome
Week 7 differentiates males and females (via sex-determining region of Y (SRY and SOX9
proteins formed))
Undifferentiated genitalia contain Müllerian ducts and Wolffian ducts
o When differentiated in females Wolffian is lost
o When differentiated in males Müllerian is lost
Not required ducts eg female ducts in a male regress caused by AMH hormone and high
androgen levels (opposite in females)
MALE REPODUCTIVE
Seminal tubules = highly coiled tubules drain into rete
testis
o Fluid in lumen of tubules
o Interstitial tissue have Sertoli cells (nurse sperm
cells)
o Germ cells end up as spermatozoon
Then drain into epididymis and sperm joined to urethra via
vas deferens
o Outside tubule = Leydig cells
Hypothalamic-pit reg of LH and FSH (gonadotrophins)
o Synthesized by gonadotrophs in ant pit
o Stimulated by gonadotrophin releasing hormone
(GnRH)
o LH and FSH work on
LH → Leydig cells = testosterone look more
active
Testosterone also suppress GnRH
secretion by suppressing
hypothalamus
Testosterone inhibits LH/FSH via
inhib alt pit
FSH → Sertoli cells = inhibin
Made of two proteins
Inhibits FSH from pit
Male hormones (androgens) required to make sperm
o All bind to androgen-binding protein
o Main androgen = testosterone
Metabolized into dihydrotestosterone (potent)
