Hypothalamus/Pit CIS Flashcards
Posterior Pituitary Hormones (2)
- Oxycontin
2. ADH
Anterior Pituitary Hormones (5)
- GH
- Prolactin
- LH/FHS
- TSH
- ACTH
Common Cause of Sheehan Syndrome
Postpartum Hemorrhage that required a blood transfusion
Hemorrhage in Sheehan Syndrome causes ______
Damage to the Anterior Pituitary
Increased levels of prolactin during lactation suppress ____
GnRH
Prolactin is inhibited by ___
Dopamine
Lab Values in Sheehan Syndrome
Overall decrease in anterior pituitary hormones
Symptoms in Sheehans (5)
- inability to lactate
- fatigue
- amenorrhea
- weight retention
- Skin and voice changes
Blood Supply for the anterior pituitary
Superior Hypophyseal Artery
Blood Supply for the Posterior Pituitary
Inferior Hypophseal Artery
Pituitary Hormones can result in _____ problems
Vision
Why are pregnant women susceptible to Pituitary Infarction?
- they produce increased amounts of estrogen, progesterone and prolactin
How does increased prolactin production put pregnant women at risk of developing Sheehan Sydrome?
Hyperplasia of lactotropes –> hyperplasia of pituitary –> increased blood demand/supply –> a hemorrhage during pregnancy can cause ischemic necrosis of the gland
Why can the posterior pituitary be spared in Sheehan’s?
Different blood supply from the anterior pituitary
Causes of Hyperprolactinemia (2)
- loss of dopamine inhibition
- Hypothyroidism
How does hypothyroidism result in hyperprolactinemia?
TRH is a stimulus for prolactin release
Case:
- Brain injury
- low levels of LH, FSH, T4, T3, TSH, and Cortisol
- high levels of prolactin
Hypothyroidism dt damage to the pituitary stalk (no Dopamine inhibition on prolactin)
In a Prolactinomaof the lactrotropes, _____ hormone levels should be normal while ___ and ___ levels should be low.
- Thyroid hormone
- LH and FSH
In hypothyroidism you see very high levels of ____ and ____.
Prolactin and TSH
Treatment of a Prolactinoma?
Dopamine agonist
Prolactin Inhibits: (4)
-LH, FSH, GnRH, Testosterone
Most common Cause of Acromegaly
Somatotroph adenoma of the anterior pituitary
How does the body GH effect fat metabolism and blood glucose?
- increases lipolysis
- increases blood glucose levels
How does the body compensate for the increased glucose levels caused by increased GH?
pancreas secretes more insulin –> beta cell hypertrophy –> increase in C peptide levels –> death of beta cells (diabetes)
High GH levels will cause insulin _____.
insensitivity
Why doesn’t height increase in Post puberty acromegaly?
the epiphyseal plates have fused
Post puberty effects of high levels of GH and IGF1 (6)
- course facial features
- insulin resistance
- glucose intolerance
increase in: - organ size
- hand/foot size
- tongue size
Fat: GH causes increased ____ which results in ____.
- lipolysis
- hyeperlipidemia
Protein : GH causes increased ____ which increases ____.
- protein synthesis
- lean body mass
Glucose: GH ____ the effects of insulin which can result in _____.
- opposes
- Type II diabetes
In cases of stress, ____ release in increased but ____ is inhibited
- GH
- IGF1
Causes of GHRH release: (3)
- fasting
- stress
- hypoglycemia
Effects of protein intake on:
- GH
- IFG1
- Insulin
- Protein Synthesis
- Growth
- Caloric Storage
- GH –> increased
- IFG1 –> increased
- Insulin –> increased
- Protein Synthesis –> increased
- Growth –> increased
- Caloric Storage –> no change
Effects of Carb intake on:
- GH
- IFG1
- Insulin
- Protein Synthesis
- Growth
- Caloric Storage
- GH –> decreased
- IFG1 –> no change
- Insulin –> increased
- Protein Synthesis –> no change
- Growth –> no change
- Caloric Storage –> increased
Effects of fasting on:
- GH
- IFG1
- Insulin
- Protein Synthesis
- Growth
- Caloric metabolism
- GH –> increased
- IFG1 –> decresed
- Insulin –> decreased
- Protein Synthesis –> decreased
- Growth –> decreased
- Caloric metabolism–> increased
Causes of GH inhibition (2)
- Under-nutrition
- acute/chronic illness
When there is an abundance of a hormone a ____ test is performed
suppression test
When there is a deficiency of a hormone, a ____ test is performed
stimulation test
Order of diagnostic tests ordered:
- hormone assays
- suppression/stimulation test
- imaging
How is a GH supression test performed?
pt is given oral glucose
What is octreotide and what is its mechanism of action?
- acromegaly drug
- somatostatin analogue that inhibits the release of GH
What is Pegvisomant?
- acromegaly drug
- GH receptor antagonist
Diabetogenic effect of GH
- decreased glucose uptake
- increased serum glucose
- increased lipolysis
- increased blood insulin levels
Increased protein synthesis and organ growth (via IGF1) resulting from GH
- increased aa uptake
- increased DNA/RNA/protein synthesis
- increased lean body mass and organ size
An increase in organ size dt to GH can result in ______ dt increase in heart size.
Heart failure
3 main actions of GH:
- Diabetogenic effect
- increased protein synthesis and organ size (dt IGF1)
- Increased linear growth before puberty
