Testicular Disorders Flashcards
What hormone stimulates Leydig cells?
Sertoli cells?
LH
FSH
What hormone stimulates LH and FSH?
GnRH
What is the function of follistatin?
inhibit production of activins/inhibins
What is the function of activins?
stimulate beta-subunit FSH production
What is the function of inhibins?
suppress FSH production
Activins are produced in ___ and act on ___.
Inhibins are produced in ___ and act on ___.
Follistatin is produced in ___ and acts on ___.
- sertoli cells; pituitary
- seminiferous tubules + sertoli cells; pituitary
- testes; testes (autocrine)
Injury to seminferous tubules results in:
elevated FSH (relative to LH)
Primary hypogondism is failure of:
yo balls (testes, sorry)
Low Gnrh →
failed FSH and LH production
Low LH/FSH →
failed testosterone production +/- spermatogenesis
Leydig cells’ function:
Sertoli cells’ function:
→ T
→ spermatogenesis
No feedback from Leydig or Sertoli cells results in:
elevated FSH/LH
Hormone abnormalities in germinal aplasia?
↑FSH
Hormone abnormalities in testicular failure?
↑LH + ↑FSH
↓T
Hormone abnormalities in hypogonadotropic hypogonadism?
↓T
nml or mildly ↓LH/FSH
Signs/symptoms of Kallman’s syndrome?
hypothalamic disease
↓T
nml LH/FSH
anosmia
Signs/symptoms of Prader-WIlli syndrome?
hypothalamic disease
↓T nml LH/FSH obesity hypotonia micropenis small hands/feet
Signs/symptoms of Lawrence-Moon syndrome?
hypothalamic disease
↓T
nml LH/FSH
retinitis pigmentosa
polydactyly
Signs/symptoms of fertile eunuch syndrome?
pituitary disease
LH deficiency
Signs/symptoms of hyperprolactinemia?
pituitary disease
inhibited GnRH release
low libido
Signs/symptoms of hemochromatosis?
pituitary disease
loss of LH/FSH testes abn (1' or 2' hypogonadism)
Signs/symptoms of Kleinfelters?
tall gynecomastia eunuchoid habitus (MR theoretically common) XXY
Signs/symptoms of XYY individuals?
oligo/azospermia
Signs/symptoms of Noonan’s syndrome?
phenotypically similar to Turner’s
XO
Signs/symptoms of XX Male syndrome?
azospermia
nml height/no MR
Signs/symptoms of pre-pubertal gonadal failure?
- delayed puberty
- gynecomastia
- disproportionately long arms/legs
- related pre-pubescent symptoms
(high-pitched voice, reduced male musculature, scant pubic/axillary hair, small testes + phallus + prostate)
Signs/symptoms of post-pubertal gonadal failure?
- progressive decrease in muscle mass
- loss of libido + impotence
- abn bone metabolism
- oligo/azospermia
- menopausal-like hot flashes
- poor ability to concentrate
Physical exam of a hypogonadal patient should include:
- arm span to height
- axillary + pubic hair
- phallus and testes
Provocative testing of a hypogonadal patient may include:
- GnRH stimulation
- clomiphene stimulation
- hCG stimulation (blocks estrogen to ↑GnRH)
Lab testing of a hypogonadal patient may include:
T
FSH
LH
PRL
Highest levels of T are during…
early morning
How does T circulate in blood?
Mostly bound to sex-hormone binding globulin and albumin
2% free (available for activity)
Normal T but elevated SHBG results in:
hypogonadism
How does SHBG change with aging?
levels increase (=less free T)
Most accurate way to measure T?
equilibrium dialysis
Low SHBG may be seen in what 3 conditions?
obesity
acromegaly
hypothyroidism
GnRH, LH and FSH are all released in a ____ pattern.
pulsitile
LH has a (shorter/longer) t1/2 than FSH
shorter (thus single low measurements may be misleading)
Test used to measure biologic activity of FSH/LH
2-site radioimmunometric assay
What affects biologic activity of FSH/LH?
post-translational glycosylation
What hormone directly down-regulates the release of LH/FSH?
PRL
Elevated PRL directly decreases ___ independent of T
libido
Primary test to assess a male’s fertility
semen analysis
To evaluate semen, it should be collected after:
2-5 days of not doin’ it (or spankin’ it)
*and evaluated w/in 2 h
Fertility =
motility of > ___%
sperm count > ____
semen vol of ___mL
50%
20 mil/mL
1.5-6
What test should be performed in a semen sample showing azospermia?
fructose
none = possible obstr of ejaculatory ducts or congenital absence of ej ducts +/- vas deferens
**fructose secreted by seminal vesicles
↓ or inappropriately nml LH/FSH
↓ T
= hallmark of…
hypothalamic or pituitary defects
↑LH/FSH
= hallmark of…
testicular failure
Soft (but nml) testes are evident of what hormonal deficit?
Firm testes are evident of what hormonal deficit?
↓ LH/FSH
↑ GnRH
