hypothalamic-pituitary relationships Flashcards
the connections between the hypothalaus and posterior lobe are what
neural
the connections between the hypothalamus and anterior lobe are what
both neural and endocrine
what kind of cells release growth hormone
somatorophs
what part of the adrenal gland does ACTH stimulate
cortex and medulla
the TRH receptor is what kind of second messenger
Gq–> PLC and calcium and PKC
the TSH receptor is what kind of second messenger
Gs, adenylate cyclase, PKA
what inhibits GnRH neurons
opoids, prolactin, stress
regulation of GH secretion what + stimulates hypothalamus
GH and somatomedins (IGF)
regulation of GH secretion what inhibits AP
somatodmedins (IGF) and Somatostatin
actions of GH: diabetogenic effect
- causes insulin resistance
- decreases glucose uptake and utilization by target tissues
- incresases lipolysis in adipose tissue
- results in increased blood insulin levels**
other actions of GH
1) increased protein synthesis and organ growh
- increase uptake aa,
2) increases linear growth
- increases metabolism in cartilage forming cells and chondrocyte proliferation
- both stimulate DNA,RNA, and protein synthesis
- both mediated by somatomedins
what is a somatostatin analogue that inhibits GH
octreotide
prolactin negatively or positvely stimulates hypothalamus
positvely stimulates to increase more prolactin release
what inhibits prolactin and what are 3 main sources
dopamine
1) hypothalamus secretes dopamine to median eminence
2) dopamine neurons release dopamine from posterior pituit –>AP through portal veins
3) lactotrophs can release dopamine, (paracrine mech)
why doesn’t lactation occur during pregnancy?
even though prolactin levels are high, progesterone and estrogen down regulate prolactin receptors
-at birth inhibition released when estrogen and progesterone levels drop
