Endocrine - Hormones III (Parathyroid, Pancreas, Adrenal, and Gut) Flashcards
How does PTH affect Ca and P?
Increases Ca Decreases P (by inhibiting resorption in the kidney)
What pathway does PTH activate?
Adenylyl cyclase and cAMP
What move Vit D3 from skin or intestine to bloodstream?
Vitamin D-binding protein
What is the major form of vitamin D found in the blood?
25(OH)-D3
Where is 25(OH)-D3 converted to 1,25(OH)2-D3? By What?
Renal tubule
By 1alpha-hydroxylase
Hypocalcemia markedly increases what?
1 alpha-hydroxylase
Where is calcitonin produced?
Parafollicular C cells of thyroid
How do parafollicular cells know to release calcitonin?
By sensing high serum calcium
When is ANP secreted? Where?
Secreted by right atrium when high NaCL and/or when volume of exctracellular space expands
What do alpha, beta, and delta cells of the pancreas secrete?
Alpha - glucagon
Beta - insulin
Delta - somatostatin
What does insulin do?
Stimulates glycogenesis and glycolysis (uptake of glucose into cells)
How many disulfide bonds are in Insulin? Where?
3 –
2 connect alpha and beta chain
1 is within alpha chain
What type of receptor does insulin bind to?
Tyrosine kinase receptor
How does insulin stimulated cascade differ from cAMP or cGMP cascades?
No second messender
Where is glycogen stored?
Liver and skeletal muscle
What does glucagon stimulate?
Gluconeogenesis and glycogenolysis
What pathway does glucagon act through?
cAMP
Where is pancreastic polypeptide produced? What does it increase?
F-cells of pancreas
Regulates glycogenolysis
Where is somatostatin produced? What does it inhibit?
Produced in delta-cells
Inhibits glucagon and insulin secretion
What are the two major adrenal medullary hormones? What additional enzyme can convert one to the other?
NE
Epi
Phenylethanolamine-N-Methyltransferase (PNMT) - converse NE to Epi
What AA is NE and Epi derived from?
Tyrosine
What does NE bind to? Epi?
NE - a1, a2, B1
Epi - a1, a2, B1, B2
What intracellular cascades do a1, a2, and B1 stimulate?
a1 - Gq (IP3)
a2 - Gi (inhibits adenylyl cyclase)
B1 - Gs (stimulates adenylyl cyclase)
What hormone stimulates appetite?
Ghrelin
What hormone stimulates acid and pepsin secretion?
Gastrin
What stimulates release of bicarb and water?
Secretin
What hormone increases secretion of digestive enzymes from the pancreas?
CCK
What hormone relaxes the GI, inhibiting acid and pepsin secretion?
VIP
What hormone/peptide suprresses glucose-induced insulin secretion?
Pancreatic polypeptide
What hormone controls feeding behavior and energy homeostasis?
Neuropeptide tyrosine
