Male Reproductive Hormone Testing Flashcards
delayed puberty
no puberty by age 14 for boys
> constitutional delay
> Hypogonadotropic hypogonadism
> Hypergonadotropic hypogonadism
Kallman’s syndrome
deficiency in GnRH + anosmia (no sense of smell)
hypogonadotropic hypogonadism
- tumors
- hypothalamic dysfunction
- pituitary disorders
- Kallman’s syndrome
hypergonadotropic hypogonadism
- primary testicular failure
- Klinefelter’s syndrome
- congenital, anorchia
- cryptorchidism
Klinefelter’s syndrome
- increase FSH, LH
- decreased testosterone
- sex-linked chromosomal anomaly
- 47 chromosomes (XXY)
- 1/500 live newborn males
- rarely diagnosed before puberty
> small testes, infertility, reduced body hair, gynecomastia, and tall stature (eunuchoid)
anabolic effects of testosterone
- increases bone density
- increases muscle mass
- increases skin thickness
- increase RBC mass
= libido, potency, fertility
androgen deficiency (from low testosterone) AFTER puberty
- ostopenia/osteoporosis
- proximal muscle wasting
- fine wrinkling of the face
- pallor, anemia
- decreased endurance
- erectile dysfunction
- infertility
- low E (may be mistaken for depression)
- decreased body hear and thus shaving
- obesity, gynecomastia
hypogonadism after puberty:
the following features are irreversible androgen effects that are NOT lost if hypogonadism occurs after puberty
- deep voice
- male sexual orientation
- penis size
- body proportions
- baldness
- linear height
decline in testosterone is thought to be due to:
- decreased Leydig cell numbers
- decreased GnRH pulse amplitude
- increases in SHBG (meds can interfere with binding of hormones)
to diagnose hypogonadism these must be met:
- patients must exhibit at least three symptoms
- low concentration of serum testosterone
- total serum testosterone is most widely used
- test free and bioavailable testosterone
> when total test… is not diagnostic in a patient with symptoms of hypogonadism
hypogonadism in general
inability to make testosterone or sperm or both
Sertoli cells (3)
- maintain high [testosterone] for sperm development
- convert testosterone to estrogen which help Sertoli cell adhesion
- release inhibin
main source of androgens
testes
other sources of androgens
- 5% DHEA and androstenedione by adrenal glands
- 80% dihydrotestosterone by peripheral conversion
mode of action of testosterone
testosterone is converted by 5-alpha-reductase to dihydrotestosterone (most potent androgen)
this binds intracellular receptor => enters nucleus
actions of testosterone
- embryonic differentiation of external and internal genitalia
0 male secondary sexual characteristics
clinical evaluation of male hypogonadism = beforep uberty
- developing fetus
> ambiguous genitalia (not enough testosterone exposure)
> male pseudohermaphroditism - prepubertal
> poor 2ry sexual development - eunuchoid body habitus
- small firm or rubbery testes
eunuchoid body habitus
A body habitus that is tall, slim and underweight, with long legs and long arms
what is the problem if GnRH is not present?
Kallman’s syndrome
what is the problem if FSH is elevated but testosterone is very low?
Klinefelter’s syndrome
male menopause
- testosterone deficiency with age
> 50% of healthy men between 50-70 have low levels of bioavailable testosterone - Leydig cell insufficiency = declines slowly after 50
- LH levels unchanged or increased = set pt for neg feedback decreased
- circadian rhythm lost = naturally high in mornings
- fatigue and decreased libido
T or F. testosterone is highest in the morning
T!
SHBG is ________ in hypogonadal men with hypothyroidism
elevaatedd
bioavailable testosterone
2% = free 38% = weakly bound to albumin
the rest is tight bound to SHBG
Erectile dysfunction
- can be psychogenic or oganic
- androgen def only accounts for 10% of ED
- systemic possibilities likely = neurologic, endcrine, vascular, systemic illness, urogenital, drugs, ethanol
T or F. androgen deficiency is a common contributor to ED
F! only 10% of the time
infertility
40% for either male, female
; even split
20% couple factors
