Menstrual Cycle, Puberty and Development Disorders -Gambone

Question 1

What is the Two Cell Theory?

Answer 1

Theca cells produce 2 types of androgens (testosterone and androstenedione) in response to LH stimulation

–> converted to estrone and estradiol by granulosa cells when stimulated by FSH

-estradiol also enhances the binding of FSH and increases granulosa sensitivity to FSH ===> + FSH-estradiol feedback

Question 2

What has permissive control over the menstrual cycle?

Answer 2

the hypothalamus

if this is interrupted, stops all cycles

Question 3

How does estrogen affect LH in the Pituitary Cycle?

Answer 3

low levels of estrogen exert a negative effect on LH release while high levels of estrogen exert a positive effect on LH release

(two pool theory attempts to explain –> ready-release and storage pools)

Question 4

What happened int he monkey experiment when the ovaries were removed? When the hypothalamus was removed? When GnRH was given at a pulsatile rate?

Answer 4

• ovaries removed–> LH increases
• hypothalamus destroyed–> GnRH stopped –> NO LH
• GnRH given at normal dose –> permissive role restored

Question 5

When does the lifetime peak of oocytes occur?

Answer 5

mid-gestational

Question 6

Do FSH and LH levels fluctuate during the fetal and newborn period?

Answer 6

no.

fetus is capable of producing LH and FSH but it is suppressed until puberty

Question 7

What is “gonadostat”? What is this due to?

Answer 7

the suppression of the hypothalamic-pituitary-gonadal axis is children between 4 and 10

due to:

1. maximized negative feedback –> low levels of sex steroids lowering FSH and LH
2. central inhibition of GnRH (also seen in a gonadal children)

-by 11th year, loss of gonadostat allows for GnRH pulses and release of LH and FSH

Question 8

When does the initial endocrine event of puberty take place? What about the initial physical event?

Answer 8

initial endocrine=androgen production by the zona reticularis of the adrenal cortex
–> leads to adrenarche/pubarche (axillary and pubic hair)

physical=thelarche in females (breast development)

Question 9

What is the sequence of changes that occurs during pre-pubertal development?

Answer 9

thelarche (8 yo) –> adrenarche (10) –> peak height velocity (11) –> menarche (12.5)–> mature sexual hair and breasts (14)

Question 10

What are the stages of breast development?

Answer 10

Marshall-Tanner staging:

stage 1: elevation of papilla

stage 2: breast bud stage, elevation of breast and papilla as a small mound with areolar enlargement

stage 3: further enlargement with separation of contours

stage 4: projection of the areolar and papilla forming a secondary mound

stage 5=mature breast

Question 11

What hormones are involved in children’s growth spurts? When does this normally occur?

Answer 11

GH, E2 and insulin growth facts I

girls is 2 years earlier than boys (1 year before menarche)

Question 12

What can be used to evaluate whether the onset of puberty is delayed or not?

Answer 12

maturation of bone using standardized nomograms

Question 13

At what is age is puberty considered to be precocious? What is generally the cause?

Answer 13

earlier than 8 yo in girls and 9 in boys (5x more likely in girls)

75% is idiopathic
but a complete workup is done to ensure there is no serious disease

Question 14

How is idiopathic (constitutional) precocious puberty treated? Why is this important?

Answer 14

GnRH agonist

-accelerated epiphyseal fusion of the bone due to excess/premature sex steroids can lead to short stature

Question 15

When is puberty considered to be delayed?

Answer 15

failure to undergo thelarche by age 14 in girls