Pituitary

Question 1

sx from tumor pressing superior to pituitary

Answer 1

optic chiasm –> CN II - visual field cuts and blindness
pituitary stalk and hypothalamus –> messed up delivery of hypothalamic releasing factors, ADH, satiety centers
sella turcica and tentorium sella –> headache, destruction of pituitary tissue

Question 2

sx from tumor pressing inferior to pituitary

Answer 2

sphenoid sinus –> CSF rhinorrhea and risk of meningitis

Question 3

sx from tumor pressing lateral to pituitary

Answer 3

cavernous sinus compression of CN III, IV VI –> ocular palsies
temporal lobe –> temporal lobe epilepsy

Question 4

menopause - what happens

Answer 4

ovaries involute. pituitary still makes LH and FSH but ovaries don’t respond. high LH and FSH b/c no estradiol and progesterone for negative feedback.

Question 5

somatostatin

Answer 5

neg feedback to pituitary in thyroid axis and growth hormone axis

Question 6

where is IGF1 made?

Answer 6

liver

Question 7

prolactin axis control

Answer 7

tonic inhibition by dopamine from hypothalamus

TRH can swim prolactin if produced in gross excess

Question 8

glycoprotein hormones

Answer 8

Pituitary hormones: FSH, LH, TSH
hCG
all have same alpha subunit, but unique beta subunits
glycosylation req for function

Question 9

pituitary apoplexy

Answer 9

acute bleeding into pre-existing adenoma –> headache, visual disturbances, acute panhypopituitaryism

Question 10

causes of acromegaly

Answer 10

somatic mutation in g protein of GH-secreting cells of pituitary

Question 11

tx of acromegaly

Answer 11

surgery or radiation
med therapy:
- dopamine antagonist
- long-acting somatostatin analog (octreotide)

Question 12

acromegaly and T2D

Answer 12

increased IGF-1 w/ ANTI-insulin effects –> insulin resistance –> resembles T2D

Question 13

ddx hyperprolactinemia

Answer 13

hypothalamic disease
pituitary disease: prolactinoma, mechanical compression
primary hypothyroidism (TRH –> upreg prolactin)
neurally mediated
drugs: antipsychotics, antidepressants, opiates, dopaminergic antagonists

Question 14

prolactin and gonadal function

Answer 14

prolactin INHIBITS GnRH secretion and LH effects

Question 15

why and how tx prolactinoma

Answer 15

why: infertility, mass effect, osteoporosis
how: surgery, radiation, dopamineric agonists –> shrinkage

Question 16

draw the PROP1/PIT1 scheme

Answer 16

see notes

Question 17

IGFBP-3

Answer 17

binding protein. growth hormone dependent. used clinically as a marker for GH deficiency

Question 18

thyroid hormone and growth

Answer 18

hypothyroidism –> impaired GH release, delayed bone maturation
hyperthyroidism –> accelerated linear growth and bone maturation

Question 19

gonadal steroids and growth

Answer 19

estrogen + testosterone spur linear growth in pubertal growth spurt
bone maturation is due to estrogens

Question 20

what is responsible for fetal growth?

Answer 20

most rapid stage of growth

not GH dependent, dependent on maternal placental factors

Question 21

what is responsible for growth in infancy?

Answer 21

transition towards pituitary depend growth and IGF-1

Question 22

what is responsible for growth in childhood?

Answer 22

sensitive to growth hormone and thyroid hormone

not sex steroids

Question 23

what is responsible for pubertal growth?

Answer 23

growth spurt due to sex hormones

• direct effect on linear growth
• increase production of growth hormones and IGF-1

Question 24

GH deficiency

Answer 24

decreased linear growth

hypoglycemia in infancy (b/c GH is counter-reg to insulin)

Question 25

gold standard test for GH deficiency

Answer 25

insulin-induced hypoglycemia (b/c GH is counter-reg)

Question 26

laron dwarfism

Answer 26

defect in growth hormone receptor –> low IGF1 and high GH

Question 27

most common cause of growth disorders

Answer 27

hypothyroidism

Question 28

hypogonadism effect on growth

Answer 28

blunted pubertal growth spurt
but delayed epiphyseal fusion –> growth continues past puberty
echinoid body habits