Puberty and Sexual Dysmorphism Flashcards
Describe the mini-puberty of infancy.
a 6-8 week period right after birth when the hypothalamic-pituitary-gonadal axis is biologically active with sex steroid levels rising, but no peripheral effects
biological relevance is unknown
The long period pf pre-puberty is mediated by what?
HPG axis suppression
When the suppression is released, puberty begins. What is the general underlying endocrinology?
- increase in activity of adrenal gland - more steorids
- increase in pulsatile GnRH and FSH/LH secretion
- Corresponding increase in estrogen in females and testosterone in males
Mitosis occurs in puberty in which gender?
males - in spermatogonia
there is no/very little mitosis of oogonia after birth
Describe how the steroids pulse during puberty?
only at night - not during the day (this is different from reproductive and postmenopausal period, when there is pulsing thorugh the day and night)
True or false: the pubertal diurnal and pulsatile secreiton of GnRH and LH/FSH that stimulates steroiodogenesis of gonads and mautration of HPG axis requires the presence of the gonads
false - doesn’t require the gonads
What are the phenotypic changes in puberty?
axial growth
secondary sex organs
gender specific and nongender specific hair growth
central processing alterations due to dentral pathway remodeling (impaired judgement0
vocal cord thickening
menarche
libido increase
What is adrenarche
pubic hair growth
Pubic hair growth is largely due tot he development of what hormone?
development of the adrenal zona reticularis and subsequent production of androstenedione and dihydoepiandrosterone
What is thelarche?
breast development due to increaseing estrogens
What is gonadarche?
production of ovarian hormones and mature gametes
What is mecharche
menses - uterine response to ovarian hormones
Describe the tanner staging in boys based on external genitalia?
1 - prepubertal
2 - enlargement of scrotum and testes; scrotum skin reddens
3 - enlargement of penis (length), further growth of testes
4 - increased size of penis with growth in breadth and development of glans, testes and scrotum larger, scrotum skin darker
5 - adult genitalia
Describe the tanner staging in girls based on breast development.
stage 1 - prepubertal
2 - breast bud stage with elevation of breast an dpapilla, enlargement of areola
3 - further enlargement fo breast and areola but no separation of their countour
4 - areola and papilla form a secondary mound above level of the breast
5 - mature stage - projection of papilla only related to recession of areola
Describe the Tanner staging based on pubic hair.
stage 1 - prepubertal (velus similar to abdominal wall)
stage 2 - sparse growth of long slightly pigemnted hair, stright or curled at base of penis or along labia
stage 3 - darker, coarser and more curled hair, spreading sparsely over junction of pubes
stage 4 - hair adult in type, but covering smaller area than in adult, no spread to medial surface of thighs
stage 5 - adult in type and quantity, with horizontal distribution
WHen does growth velocity peak in girls?
between 11 and 12
When does breast development begin in girls on average?
age 10
WHen does menarche occur on average?
age 12
When does completion of puberty occur in girls on average?
14
Why does growth stop at the end of puberty?
high estrogen closes the growth plate
When does the peak growth time happen in ales?
age 13-14
When can you start seeing an increase in testicular volume?
11-12
When does pubic hair start in males?
age 12
When can you start to see semen in the urine?
age 14-15
When does puberty end in males?
15-16
Puberty is occurring earlier and earlier. What is the likely cause?
nutrition - sheer availability of calories
higher BMI or higher height - the earlier the onset
What are the two versions of precocious puberty?
gonadotropin dependent precocious puberty
or independent
What are the two generally causes of gonadotropin dependent precocious puberty?
80% are idiopathic
20% are CNS-related: hypothalamic hamartomas, CNS tumors, cranial irradiation, hydrocephalus and trauma (things that would stimulate hormone production)
What are some causes of GIPP in girls only?
ovarian cysts
ovarian tumors
What ar esome cuases of GIPP in males only?
leydig cell tumors, germ cell tumors,
What are some causes of GIPP in both genders?
exogenous estrogen
adrenal pathology with excess androgen
pituitary tumors
What would be the endocrine effects of GDPP?
pulsatile GnRH
increased LH and FSH to a lesser extent
increased sex steroid output
What are some of the signs of GIPP?
virilization
bone age older than chronological age
Displays od adrenarche too early can suggest what?
tumors of the adrenal gland
congenital drenal hyperplasia
What is the relationship to the prepubertal bone plates and E2?
low levels increase growth
high levels promote closure
So are precious puberty kids short or tall?
short
What two lab tests can we do to diagnose precocious puberty?
GnRH analog stimulation test
random LH screening test
What would hte GnRH stimulation test show in GDPP?
FSH and LH will be increase
What would that GnRH stimulation test show in GIPP?
FSH and LH not increased
Random high LH screening would suggest which?
central precocious puberty - GDPP (I think)
What is the differenc between premature thelarche and precocious puberty?
premature thelarche happens in 6 mo - 2 yo and involve only the breast
precocious puberty happens 5-8 yo and will include thelarche plus another puberty change
What are the treatment options for treatment of GDPP?
drugs for medical castration:
GnRH agonists (nonpulsatile) or antagonists
Anti-estrogens/anti-androgens
Glucocorticoids in the case of CAH (depending on the enzyme deficiency)
What are the three general sexual dimorphism determinants?
sex chromosome makeup
gonadal sexual differentiation (in utero)
phenotypic manifestation during fetal stages and puberty
What are some general causes of sexual ambiguity?
- mutatiosn in hormone production, receptors, signaling
- hypogonadism
- sex chromosomes loss
- mosaicism from embryological events like chromosomal loss
What is necessary for male gonadal differentiation?
sex determining region of the Y chromosome - SRY protein
note that the default is female
What happens to the mullerian duct in females and male?
female - develops into reproductive organs
male - degenerates due to anti-mullerian hormone
What happens to the Wolffian duct in females and males?
females - degenerates
males - converts to seminal vesicle, vas deferens ,epididymis under the influence of testosterone
What is another name for SRY protein
testis-determining factor
What are three hormonal causes of sexual ambiguity?
congenital adrenal hyperplasia
androgen insensitivity syndrome
5-alpha reductase deficiency syndrome
What is the most common CAH enzyme deficiency?
cyp 21 hydroxylase
What is the second most common CAH enzyme deficiency?
11 beta-hyddroxylase
What are some other enzymes that can be deficiency?
Cyp11A1 - side chain cleavage enzyme
17alpha hydroxylase
17beta hydroxylase
3beta hydroxysteroid dehydrogenase
What three hormone deficiencies would cause both CAH and low testosterone?
side chain cleavage enzyme
3beta hydroxysteroid dehydrogenase deficiency
17alpha hydroxylase deficiency
What enzyme deficiency would just cause a decrease in testosterone?
17-beta hydroxylase deficiency
What should you do for someone with these?
supplement testosterone at puerty
What cells make the mullerian inhibitin substance?
the sertoli cells
What are the three enzyme deficiencies that can results in congenital adrenal hyperplasia and viriliation of females?
21 hydroxylase deficiency
11 alpha hydroxylase deficiency
3beta hydroxysteroid dehydrogenase deficiency
What happnes in androgen insensitivty syndrome?
androgen receptor mutation such that XY babies develop as phenotypical “super” females without menses
inguinal, abdominal, or labial testes and external genitalia female
ow is androgen insensitivty syndrome inherited?
x-linked
5 lapha reductase deficiency leads to what?
babies classified as girls at birth, but start developing male characteristics at puberty
XO is what?
turner syndrome
XXY is what/
kleinfelters
What is the penotype in turner syndrome?
gonadal streaks
no androgens or estrogen
female external genitalia
but no real breast development
