Hypothalamus and Pituitary Flashcards
Hormones released from the anterior pituitary do what?
stimulate the production of hormones by a peripheral endocrine gland, the liver, or other tissues
Hormones released from the posterior pituitary act how?
act directly on target tissues
what do hypothalamic factors do?
regulate the release of anterior pituitary hormones
what are the positive and negative feedback hypothalamic hormones affecting Growth hormone?
positive: Growth hormone releasing hormone
negative: somatostatin
what are the functions of growth hormone? (3)
Required for normal growth
Regulates lipid and carbohydrate metabolism and lean body mass
Regulates production of insulin-like growth factor 1 (IGF-1) in peripheral tissues
what is Somatropin?
recombinant form of Human growth hormone
what are some indications for use of somatropin?
- short stature
- failure to thrive
- small-for-gestational-age
- HIV wasting
- short bowel syndrome= improves GI function
Adverse effects of Somatropin in children?
- pseudotumor cerebri
- slipped capital femoral epiphysis
- progression of scoliosis
- hyperglycemia
If given glucocorticoids in addition to GH, what might you find?
it may inhibit the growth-promoting effects of GH
If you give GH in addition to other hormones, what might happen?
may accelerate epiphyseal closure and compromise final height
what is mecasermin?
recombinant human IGF-1
when do you use mecasermin?
children w/ growth failure unresponsive to GH therapy and are deficient in IGF-1
ADE of mecasermin?
- hypoglycemia
- tonsillar/adenoidal hypertrophy, lymphoid hypertrophy
- coursing facial features
what are the dopamine agonists?
bromocriptine
cabergoline
what are GH antagonists?
Octreotide, Lanreotide, Pasireotide
Pegvisomant
If a pt has a growth hormone-secreting pituitary adenoma, what is it called in adults? children?
adults= acromegaly children= gigantism
what diagnostic tool can be used to test IGF-1?
oral glucose tolerance test
what would you find after giving the glucose in OGTT?
Oral glucose load would be expected to suppress GH concentrations
Patients with acromegaly continue to secrete GH during the OGTT
rank the effectiveness of dopamine agonists, somatostatin analogs, and GH-receptor antagonist in lowering GH concentrations
(least) dopamine agonists < somatostatin analogs < GH-receptor antagonist (most)
what happens in pts with acromegaly when using dopamine agonists?
paradoxical decrease in GH production
normalize IGH-1 concentrations
Unique ADEs of dopamine agonists
thickening of bronchial secretions and nasal congestion
how do somatostatin analogs work?
inhibit the release of GH, glucagon, insulin, and gastrin
ADEs of somatostatin analogs
- Gallstones (inhibition of CCK release)
- Cardiac conduction abnormalities
- Hypertension
- Abnormalities in glucose metabolism
- Subclinical hypothyroidism
What is Pegvisomant and how does it work?
GH antagonist
- Inhibits IGF-1 production
- Blocks the physiologic effects of GH on target tissues
What is a unique ADE of pegvisomant?
Increased liver enzymes
what is the primary treatment of acromegaly?
surgery
Causes of hyperprolactinemia?
prolactin stimulators (lots of types of drugs)
dopamine antagonists (mostly from antipsychotics)
what are treatment options for hyperprolactinemia? What is most effective?
- dopamine agonists (more effective than surgery)
- radiation therapy
- transsphenoidal surgical removal of the tumor
How do dopamine agonists work in pts w/ hyperprolactinemia?
Hypothalamic release of dopamine inhibits the release of prolactin
ADE of Bromocriptine
infertility
ADE of Cabergoline
Mild-to-moderate decreases in blood pressure
If you lose your pituitary gland due to a tumor, what do you have? What does it require?
panhypopituitaryism
replacement of all hormones exogenously
What 2 hormones are released by the posterior pituitary?
oxytocin
vasopressin
What is used to dx TRH or TSH deficiencies?
Thyrotropin-releasing hormone
What are dopamine agonists used for?
Tx of hyperprolactinemia
What are GnRH analogs used for?
Inhibiting gonadal function in precocious puberty, transgender/gender variant, prostate CA, & in women undergoing assisted reproductive technology (ART)
