Hypothalamic-Anterior Pituitary Axis Flashcards
T/F. All the hormones in the hypothalamic-anterior pituitary system are lipid soluble.
False; all the hormones in the hypothalamic-anterior pituitary system are water soluble
In the hypothalamic-anterior pituitary system, hormonal release is mainly constant or pulsatile?
What is the exception?
pulsatile;
thyroid hormone
The arcuate region of the hypothalamic nuclei secrete what hormone?
DA and GHRH
The paraventricular region of the hypothalamus releases what hormones?
CRH, TRH, and SST
What is the suspected reasoning behind why hypothalamic nuclei have pulsatile stimulation of receptors?
to prevent downregulation of receptors in the anterior pituitary
High frequency pulses of GnRH stimulate what gonadatropin? What do low frequencies stimulate?
high frequency pulses favor LH, low frequency pulses favor FSH
The preoptic region of the hypothalamus produces what hormone?
GnRH
What are some causes of hypopituitarism?
head trauma (most common), mass effects of tumors, inflammation, or vascular damage
What is Kallman syndrome?
(tertiary) defective GnRH synthesis
ACTH, TSH and prolactin defiencies are usually indicative of what?
panhypopituitarism
What is the most common hypothalamic-pituitary system tumor in children?
craniopharyngioma
What is Sheehan syndrome?
the pituitary in pregnancy is enlarged and more vulnerable to infarction. When pregnant woman delivers is associated with severe blood loss, the ensuing shock may cause arteriolar spasm with subsequent ischemic necrosis
What can pituitary adenomas lead to? Is it usually benign or malignant? What are some clinical features?
- usually benign but can autonomously secrete hormone
- they can lead to hyper-prolactinemia, acromegaly, Cushing’s disease
- hypogonadism (most common feature)
galactorrhea also a symptom of prolactinoma - MEN 1 association
What is the most
What are the features of micro-adenomas of the pituitary?
hormonal excess, no pan-hypopituitarism, treatable e.g ACTH (Cushing Disease)
