Endocrine

Question 1

What covers the pituitary gland in the brain?

What facial bone is close to the pituitary gland?

Answer 1

sella tursica

sphenoid bone

Question 2

How is the pituitary divided into?

Answer 2

Anterior and posterior pituitary

Question 3

What hormones are secreted by the posterior pituitary? Where are the hormones made?

Answer 3

ADH & oxytocin
ADH made in supraoptic nucleus
oxytocin made in the hypothalamus

Question 4

What is the hypothalamic - pit axis?

Answer 4

hypothalamus regulates the release of hormones from anterior pituitary by different hypothalamus releasing and inhibiting hormones

Question 5

What are the hormones being released from anterior pituitary ?

Answer 5

FSH
LH
TSH
GH
Prolactin
ACTH

Question 6

How does the releasing and inhibition work from hypothalamus to the target gland?

Answer 6

Hypothal ——> Pituitary ——-> Target Hormone —> increase

causes negative feedback to the hypothalamust to stop secreting releasing hormones.

Question 7

What are microadenomas? macroadenomas? Which is more common?

Answer 7

micro 1 cm - usually compress the optic chiasm

microadenomas are more common than macro

Question 8

Hyperprolactinemia definition?

Answer 8

excess prolactin secretion common in women causing galactorrhea - amenorrhea

Question 9

How is the amenorrhea in hyperprolactinemia caused?

Answer 9

due to the inhibition of GnRH with decrease in LH/FSH

prolactin also inhibits LH surge that causes ovulation

Question 10

What does hyperprolactinemia cause in men?

Answer 10

most common presentation is erectile dysfunction and decreased libido
can also cause gynecomastia and galactorrhea

Question 11

What is the etiology of hyperprolactinemia?

Answer 11

1. natural physiologic state can in preg, early nursing, hypoglycemia, seizures, exercise, stress, sleep, cirrhosis, nipple stimulation, chronic renal disease (due to decrease PRL clearance)
2. autonomous production seen w pituitary adenomas (prolactinomas) - acct for 60% of pituitary tumors, micro occur in women, macro in men (causes visual prob) other tumors to causes increase prolactin
   craniopharyngioma
   meningioma
   dysgerminoma
3. drugs that inhibit dopamine - (dopamine blockers) phenothiazines, metoclopramide, (dopamine depleting agents - alpha methyldopa, reserpine), TCA, narcotics, cocaine, SSRI, risperadone
4. stimuli that overcomes normal dopamine inhibition - primary hypothyroidism —> leads to increase in TRH which causes increase in prolactin

Question 12

Clinically what does hyperprolactinemia look like?

Answer 12

s/s are galactorrhea, menstrual abnormalities, ameno/oligomenorrhea, osteopenia, osteoporosis in long standing cases, infertility and gynecomastia in women
in men = hypogonadism, erectile dysfunction, decreased libido, gynecomastia, infertility

Question 13

How to diagnosis hyperprolactinemia?

Answer 13

1ST exclude pregnancy, lactation, hypothyroidism, medications before starting workup

• prolactinomas can co-secrete GH
• levels > 100 suggests pituitary adenoma