Lec 19 Reproductive I Flashcards
What is the function of leydig cells?
secrete testosterone
What are the functions of sertoli cells?
- MIF
- androgen binding protein
- inhibin
- blood-testis barrier
- nourish germ cells
- aromatize T to estrogens
What is testis determining factor?
induces development of testes from indifferent gonad; gene on Y chromosome
What is function of MIF in fetal testis?
causes regression of mullerian structures
What is function of testosterone in fetal testis?
induces development of wolffian structures
What is difference between action of testosterone and DHT in fetal development?
- bind same androgen receptor but DHT has higher affinity
- T needed for wolffian duct development
- DHT needed for external genitalia and prostate development
What is difference between action of testosterone and DHT in puberty/adulthood?
- testosterone needed for MSK development, pubic/axillary hair, spermatogenesis, libido
- DHT needed for full secondary sexual hair, acne, temporal hairline recession, prostate enlargement and diseases
What is the phenotype at birth of someone with 5-alpha-reductase deficiency?
variable phenotype may be undetermined sex –> become phenotypic males at puberty
What happens in 5-alpha reductase deficiency?
XY genotype
low DHT:T ratio b/c can’t convert
as adults normal libido and fertility/musculature but NO balding or prostatic disease!
What is androgen insensitivity syndrome?
genotypic male but phenotypic female
mutation of androgen receptors –> have high LH, FSH, T
present with primary amenorrhea and have undescended testicles
What is the first measurable indication of puberty?
DHEA-sulfate = weak adrenal androgen
What is effect of FSH in males?
stimulates sertoli cells to produce inhibin which feeds back on GnRH secretion from hypothalamus
What is effect of LH in males?
stimulates testosterone production by leydig cells which feeds back on GnRH secretion from hypothalamus
What is effect of FSH in females?
FSH stimulates granuosa cells to produce estrogen and follicles to secrete inhibin
What is effect of LH in females?
LH triggers ovulation and later stimulates theca cells to secrete androgesn
What happens if you give GnHR in non-pulsatile manner?
causes medical castration = intially increase FSH/LH then cause desensitization
used to treat uterine fibroids and prostate cancer
What is kallman’s syndrome?
most common cause of hypogonadotropic hypogonadism
can be hereditary or sporadic
deletion in KAL gene
phenotypic male at birth; fail to mature at puberty b/c lack GnRH
eunichoidal proportions due to lack of pubertal testosterone
associated with anosmia
What DSD is associated with anosmia?
kallmans syndrome
How does kallman’s syndrome present?
failure to go through puberty
What is klinefelter’s syndrome?
47 XXY
prematurely senescent testes
seminiferous tubule dysgenesis; azospermia; and lerydig cell failure
low/normal testosterone, high FSH and LH and estrogen
mental retardation
What does azospermia and high FSH suggest?
primary testicular failure as cause of low sperm
