Week 2 Flashcards
What is the primary glucocorticoid?
cortisol
-negative feedback control of hypothalamic (CRF) and anterior pituitary (POMC/ACTH) release
What enzyme is responsible for converting progesterone to glucocorticoids?
21 hydroxylase
- defective = lack of glucocorticoids and mineralocorticoids and excess of androgens
- hypotension
What enzyme converts deoxycorticosteroids to glucocorticoids and mineralocorticoids?
11B-hydroxylase
What are the 3 zones of the adrenal glands from outside to inside?
Zona glomerulosa (mineralocorticoids/aldosterone) Zona fasciculata (glucocorticoids/ cortisol) Zona reticularis (androgens)
What cells are found in the adrenal medulla and secrete epinephrine or norepinephrine?
chromaffin cells
What amino acid are norepinephrine and epinephrine made from?
tyrosine
tyrosine to dopa to dopamine
What cell is dominant in pheochromocytomas?
chromaffin cells of the adrenal medulla
What adrenal zones are activated by ACTH?
all three layers of adrenal cortex (release aldosterone, cortisol, glucocorticoids, and androgens)
Which of the 3 sets of adrenal capillaries empties into the veins of a capsule without picking up hormone?
capsular plexus
Which of the 3 sets of adrenal capillaries drains into veins of medulla?
cortical sinusoidal (fenestrated)
Which of the 3 sets of adrenal capillaries empties into medullary venules?
medullary capillaries (fenestrated)
Which part of the pancreas has more islets?
tail
What are the products of pancreatic alpha, beta, and delta cells?
alpha- glucagon
beta- insulin
delta- somatostatin
What is the rate limiting step in adrenal steroid synthesis?
ACTH binding and promoting side chain cleavage enzyme (CYP11A=P450scc) synthesis
-required to convert cholesterol to pregnenolone
What enzyme converts inactive steroids to active?
11 beta hydroxylase type 1
What is the effect of high versus normal ACTH?
-normal = ACTH is tonic high = ACTH is stimulatory
What type of receptor is the insulin receptor?
tyrosine kinase
What substance is made with insulin by beta-cells in pancreas and down-regulates alpha cells (glucagon)?
amylin
-also induces satiety
What is made by distal small bowel and colon in response to glucose presence?
GLP-1 (receptors in beta pancreatic cells and brain)
What is made by intestinal K cells in response to glucose presence?
GIP (receptors in beta pancreatic cells and brain)
Which GLUT is the glucose sensor for pancreatic beta cells?
GLUT 2
-also present in hepatocytes and found on basolateral epithelia of kidneys and intestines
What does FOXO1 do?
transcription factor for expression of key gluconeogenesis genes
-inactivated by PKB (Akt)
What effect does glucagon signaling have on the liver?
reduces fructose 2,6-bisphosphate (inhibiting glycolysis and promoting gluconeogenesis)
What does aromatase do?
converts testosterone to estradiol; active in adipocytes
What is the main side effect of insulin?
hypoglycemia
What drugs decrease hepatic glucose production by inhibiting gluconeogenesis?
Biguanides (metformin)
What drugs increase uptake of skeletal muscle insulin and increase cell responsiveness?
PPAR agnists (thiazolidinedione)
What drugs promote insulin secretion by closing K+ channels?
Sulfonylureas (Glimepiride) and Meglitinides (Repaglinide, Nateglinide)
What drugs promote insulin secretion by activating adenlyate cyclase?
GLP analogs and Dipeptidase IV inhibitors (which increase GLP)
Which diabetes drugs may cause weight gain? loss?
Gain: insulin, pioglitazone, sulfonylureas
Loss: Liraglutide/Exenatide
Which 3 diabetes drugs are more expensive?
Pioglitazone ($7.20/ day)
Liraglutide/ Exenatide ($9/day)
Gliptins ($6.20/day)
(insulin is also expensive)
Which 2 types of diabetic drugs (other than insulin) are injected?
- GLP-1 analogs (Exenatide, Uraglutide)
- amylin analog (Pramlintide)
What are the role of incretins?
increase insulin production, speeds insulin release, decreases glucagon production, slows gastric emptying, promotes satiety
Where are paraganglia and what do they secrete?
in adrenal medulla; secrete epinephrine
-aortic chromaffin bodies
What do PP (F) cells of the pancreas secrete?
pancreatic polypeptide (relaxes gall bladder and inhibits enzyme secretions from exocrine pancreas)
What is the ranges for prediabetes and diabetes with plasma glucose and HbA1C?
- prediabetes: A1c 5.7-6.4% and 100-125 gm/dL
- diabetes: A1c >6.5% usually means diabetes
