every area of the brain, CSF through tanycytes, through the blood (systemic circulation), cold TRH, diet GHRH, BP
Monoamine Neurotransmitters Derived from Amino Acids
Dopamine, Norepinephrine, Serotonin, Histamine, Epinephrine, Acetylcholine
Where does Hypothalamic Output towards the Adenohypophysis Start
Arcuate Nuclei and Paraventricular Nucleus, where tuberoinfundibular tracts start with parvicellular neurons
Where does Hypothalmic Output towareds the PP Start
magnocellular in SON and PVN, then to PP where it connects with inferior hypophysial artery
Long Loop Feedback
Ultimate target tissues( e.g. goand or thyroid) feedback on pituitary, hypothalamus or CNS
Where is Ghrelin expressed and What does it do?
Expressed in stomach, small intestine and a few hypothalamic neurons. In addition to GH stimulation Ghrelin also regulates feeding behavior and fat cell activity.
GH and IGF-1 can activate hypothalamic SST expression to negatively regualte GH in a negative feedback loop
SST affects which tissues
brain, endocrine and exocrine pancreas, gastrointestinal tract, pituitary (SST secreting cells)
PRL secretion increases from
TRH, VIP, GNrH, and oxytocin increase PRL no releasing hormone found yet
Control of PIF
seretonin is an inhibitor of dominergic neurons, when they are active the can inhibit DA release cuasing PRL release
Hyperprolactinemia: Sx and cure
breast milk production despite not being pregnant, Bromocriptine- DA agonist
GnRH is released in pulses
less frequent pulses lead to higher relative FSH release, Preferential release due to different FSH and LH gene expression rates, overall higher LH
GnRH is complex
DA from hypothalamic neurons stimulate GnRH, Met-enkephalin inhibts DA, Labled estrogen accumulates in Hypothalamic neurons that secrete GnRH
Where is the Corticotropin Releasing Hormone expressed?
Paraventricular Nucleus, expressed in parvicellular neurons in the PVN
As stress increases...
more POMC and ACTH secretion, stress induced catecholamine (epi and Nepi), Catecholamines from axons innervating the PVN axons induce CRH secretion
Mech. of Action of Releasing Hormones
all of them use PLC to increase calcium and cuase ion gating that elicitys ap's in the target cells. exception is GHRH and SST which regualate AC-cAMP