Pituitary Hormone Function (GH/PRL) Flashcards
Growth hormone is produced by ______________.
the somatotrophs of the anterior pituitary
Growth hormone binds to what kind of receptor?
A cytokine receptor family
What does growth hormone do?
Increases gluconeogenesis
Acts a counterregulatory hormone for insulin
Stimulates release of fatty acids by activating hormone-sensitive lipase
Stimulates amino acid uptake into muscle
Growth hormone also causes the release of ______________.
insulin-like growth factor (IGF)
The hypothalamus sends opposing signals to the pituitary in terms of GH release: _______________.
GHRH stimulates the release of GH and somatostatin (SST) inhibits it
How does growth hormone affect the levels of GHRH and SST?
It inhibits the release of GHRH and stimulates the release of SST.
GH inhibits the hypothalamic release of GHRH. What stimulates the hypothalamic release of GHRH?
Hypoglycemia and increased amino acids (arginine, specifically) in the serum
Why are high levels of growth hormone fatal?
Because soft tissue responds to this, which cause cardiomegaly.
Acromegaly results from excess ______________.
growth hormone after puberty
Why does placental lactogen cause gestational diabetes?
Because it has a large homology to growth hormone
Why is bromocriptine given to those with prolactinemia and neuroleptic malignant syndrome?
Because bromocriptine is a dopamine agonist
What is unique about the regulation of prolactin?
The release of prolactin is tonically inhibited by the hypothalamus. Thus, if the hypothalamus is severed from the pituitary, then levels of prolactin will rise while other pituitary hormones will fall.
What adenohypophyseal cells store GH?
Somatotrophs (GHRH and somatostatin)
GH actions on IGF-1 work to _______________.
stimulate bone growth, muscle growth, and gluconeogenesis
What adrenergic signals lead to increased release of GH?
Alpha-2 agonists or beta-antagonists
