Page 5 - HPA Axis Flashcards
What does the activation of the HPA begin with?
Secretion of CRH and other hormones/neuropeptides with similar or synergistic functions (Urocortin) from neuron’s within the paraventricular nucleus (PVN) of the hypothalamus
AVP is transported to the _ _ by _
posterior pituitary, neurons
CRH and Urocortin are transported to the _ _ by hypothalamic-pituitary portal blood circulation
anterior pituitary
In the _ pituitary CRH can bind to high affinity ___-__ on _ cells
Anterior, CRH-R1, corticotroph cells
Corticotroph cells are responsible for converting ____ to _ (aka corticotrophin) and releasing it into the _
POMC, ACTH, blood stream
What is POMC
POMC is a pro hormone that is a larger molecule precursor for ACTH
POMC undergoes cleavage by enzyme _, to become bioactive _
PC1, ACTH
What kind of receptors does ACTH bind on Adrenal Cells within the adrenal cortex?
Melanocortin 2 receptors (MC2R)
Tissue GC [] are locally regulated by expression of isozymes _ and _, to catalyze conversion of bioactive cortisol into inactive _
11B-HSD2, 11BHSD1, cortisone
11BHSD2 converts to inactive _
Cortisone
11BHSD1 converts cortisone into active _
Cortisol
Under normal conditions circulating ACTH and GC are regulated through the day and season by _ _ _
circadian clock genes
Where are circadian clock genes expressed
suprachiasmatic nuclei (SCN)
Where is the suprachiasmatic nuclei (SCN) located in the _, located just above the _ _
Hypothalamus, optic chiasma
Central Clock Genes are responsive to _ cues
environmental
