Pituitary Adrenal & Pancreas- Leah : ) Flashcards
List the 6 anterior pituitary hormones
- GH
- LH
- FSH
- ACTH
- TSH
- PRL
List the 2 posterior pituitary hormones.
Where are they synthesized?
- Oxytocin, ADH
- synthesized by hypothalamic neurons
- sent to pituitary via neuronal axons
Embryologic source of the anterior pituitary
oral ectoderm –> rathke’s pouch
Location of pituitary gland in relation to brain and skull:
In what structure does it sit?
- below hypothalamus
- Sella Turcica of the sphenoid bone
- Surrounded by diaphragma sella
How is the pituitary connected to the hypothalamus?
-Infundibulum/ stalk: neuronal connection to POSTERIOR pituitary
(But note compression of the stalk affects anterior + posterior pituitary)
Why is the anterior pituitary subject to ischemia?
- low pressure venous system (portal system) supplies the tissue
- no direct arterial supply
(same system delivers trophic hormones from the hypothalamus)
What are the three main cells of the anterior pituitary?
What hormones do each secrete?
- acidophils (GH, PRL)
- basophils (ACTH, FSH, LH)
- chromophobe (TSH)
The release of what two anterior pituitary hormones can be INHIBITED?
What are the inhibitory signals?
-DA inhibits the release of prolactin
-SOMATOSTATIN inhibits the release of GH
(DA and somatostatin come from the hypothalamus)
What are the stimulatory hormones of the hypothalamus?
Stimulatory hormones from the hypothalamus are “releasing” hormones: TRH, GnRH, etc.
Hyperpituitarism:
most common cause
three other causes?
- Adenomas = #1 (10% intracranial neoplasms)
- Also: Hyperplasia, carcinoma, non-pituitary/hypothalamic causes
What is a macro vs microadenoma of the pituitary?
What syndrome might these tumors be assc with?
Age group
- MICRO is LESS than 1 cm
- MACRO GREATER than 1 cm
- 3% related to MEN1
- Affects ADULTS of most any age (craniopharyngioma = childhood pituitary lesion)
Mass effects of adenoma (all types, 4):
- Erosion/ expansion of sella on CT
- Bitemporal hemianopia “MOST IMPORTANT THING”
- ^^ ICP
- Compression –> HYPOpituitarism
Where do larger pituitary tumors expand?
-expand SUPERIORLY–> compress chiasm
hard to go posterior due to enclosure of pituitary in the sella
Pituitary adenoma:
general gross appearance
malignant or benign?
histo appearance?
-round, well-circumscribed
-benign
-monomorphic cells + loss of reticulin fibrin network
(may see compressed normal fibrin network)
*Monomorphic: all cells one type, basophils vs. acidophils etc.
Pituitary adenomas are aggressive when assc with what genetic mutation?
–Rb
we always learn about this gene for eye tumors but it can be in most any tumor!!
(for example, I had an Rx question about the Rb gene in osteosarcoma– another aggressive tumor)
Atypical adenoma: describe it (3 features); what is the prognosis?
- ^^ mitoses
- ^^ KI67 stain (just means lots of dividing cells)
- p53 reactivity
(worse prognosis than normal adenomas)
Only criteria for pituitary adenocarcinoma?
Assc mutation?
- evidence of distal mets
- ACTIVATING mutations in HRAS
Most common TYPE of hyperfunctional pituitary adenoma?
Two histo findings?
- prolactinoma
- eosinophilic (acidophils secrete PRL)
- psammoma bodies
Signs/ Sx specific to prolactinoma (3):
- amennorhea, infertility
- loss of libido
- galactorrhea
Who is diagnosed late in the case of prolactinoma?
-post-menopausal women (don’t notice infertility/ amennorhea)
Causes of ^^ PRL that are not caused by prolactinomas (4)
- physiologic stress (preggos, nursing, etc)
- hypothalamic injury/ loss of DA
- Drugs that decrease DA (phenothiazines, haloperidol)
- renal failure, thyroid failure, ^^estrogen
Treatment for prolactinoma (2- 1 drug, 1 surgery)
- Bromocriptine (DOPA agonist)
- transphenoidal surgery
Second most common typical hyperfunctional adenoma:
- assc cell type?
- 2 classic symptoms (adults vs kiddos)
- GH adenoma
- acidophils
- acromegaly (adults) or gigantism (kids)
5 possible diseases assc with GH secreting adenomas:
aside from the 2 classic symptoms
- glucose intolerance/ DM
- HTN
- osteoporosis + arthritis
- CHF
- muscle weakness
(I think of this as basically all of the disease that fat old people get. Growth hormone causes the diseases you see in people that grow old and grow fat.)