2 - Anterior Pituitary 1

Question 1

which pituitary hormones are grouped together by differentiation pathways?

Answer 1

GH and prolactin
TSH and LH/FSH
ACTH and melanotropes

Question 2

common alpha subunit is shared by what hormones?

Answer 2

TSH, LH, FSH, beta-HCG

Question 3

size cutoff btwn micro and macroadenoma in pituitary

Answer 3

1 cm

Question 4

4 MC pituitary adenoma cell types / secretion types

Answer 4

35% prolactin
28% “non functioning” (alpha subunit)
17% GH
9% ACTH

Question 5

visual field defect assoc w/ pituitary tumor

Answer 5

superior temporal quadrantanopsia or temporal hemianopsia

Question 6

sx of hyperprolactinemia

Answer 6

women: galactorrhea, amenorrhea
men: dec libido, impotence, rarely have galactorrhea

Question 7

causes of hyperprolactinemia (fairly general)

Answer 7

PREGNANCY (must r/o before working up for prolactinoma)
hypothyroidism (TRH stimulates prolactin release)
prolactinoma
other pituitary masses interfering w/ DA inhibition
cosecretion w/ GH (ex in acromegaly)
anti dopaminergic drugs
chronic renal failure

Question 8

Hook effect

Answer 8

immunoassays can give false negs if levels of target are too high - abs get covered by so much antigen that nothing can agglutinate

Question 9

only pituitary adenoma where surg is not considered first line tx

Answer 9

prolactinoma

Question 10

tx of prolactinoma

Answer 10

dopamine agonists - bromocriptine (used in pregnancy but causes nausea and orthostasis), cabergoline (better tolerated)

Question 11

cabergoline

Answer 11

DA agonist used for hyperprolactinemia

Question 12

normal stimuli for GH secretion

Answer 12

diurnal - inc during sleep

physical activity and emotional stress stimulate it

Question 13

what molecule mediates most growth effects of GH?

Answer 13

insulin like growth factor 1 (IGF-1)

Question 14

GH effects independent of IGF1

Answer 14

glucose homeostasis (insulin resistance), Ca metab (inc bone density), lipolysis

Question 15

cause of GH excess

Answer 15

mostly sporatic adenomas

Question 16

causes of sx in GH excess

Answer 16

neuropathy
enlarged visceral organs (heart important here)
glucose intolerance

Question 17

how to dx acromegaly

Answer 17

single serum GH > 100 ng/ml (rarely done b/c often dont catch it)
elevated IGF-1 (longer half life so more sensitive)

Question 18

medical therapy for acromegaly

Answer 18

somatostatin analogues - octreotide, etc
pegvisomant (GH-R antagonist)
dopamine agonist (bromocriptine, cabergoline)

Question 19

complications of acromegaly

Answer 19

inc mortality rate (2-3x)
often CV problems, respiratory, inc risk of malignancy
can develop overt DM

Question 20

McCune Albright

Answer 20

inherited cause of GH pituitary adenoma
G protein subunit mutation
cafe au lait spots, precocious puberty, acromegaly/gigantism, thyrotoxicosis

Question 21

Carney Complex

Answer 21

inherited cause of GH pituitary adenoma
PKA type 1 regulatory subunit problem
spotty skin pigmentation and blue nevi, cardiac myxomas, schwannomas, testicular/ovarian tumors

Question 22

Multiple endocrine neoplasia (MEN 1)

Answer 22

AD inheritance
menin gene mutation (tumor suppressor)
3 Ps - pituitary adenoma (mostly prolactin, next MC is GH), parathyroid hyperplasia, pancreatic neuroendocrine tumors (mostly gastrinoma, maybe insulinoma)