Endocrine

Question 1

How does insulin act on the cell?

Answer 1

It causes the insulin receptor to autophophorylate–> activation of PI3K(—> Activation of protein phosphatase, which dephosphorylates glycogen synthase) and activation of MAP kinase (mitogenic)

Question 2

What inhibits carnitine?

Answer 2

Malonyl CoA

Question 3

What are the histological findings in Hashimotos thyroiditis?

Answer 3

Intense mononuclear infiltrate (lymphocytes and plasma cells) with germinal centers. Residual follicles are often surrounded by hurthle cells (large oxophyllic cells with granular cytoplasm)

Question 4

Which step in the TCA cycle is Thiamine dependent?

Answer 4

alpha ketoglutarate–> succinyl coA

Also, pyruvate—> Acetyl CoA

Question 5

What muscle issues are found in hypothyroidism?

Answer 5

muscle pain, cramps, and weakness involving the proximal muscles
Delayed DTRs and myoedema
Elevated CK

Question 6

What are the cardiovascular effects of excess androgen?

Answer 6

Increased Hct and LDL, decreased HDL

Question 7

What are neurophysins?

Answer 7

Carrier proteins for oxytocin and vasopressin (produced in paraventricular and supraoptic nuclei, respectively, and released by the posterior pituitary)

Question 8

What causes MODY?

Answer 8

Mutations that impair glucose sensing and release of insulin from the pancreatic beta cells

Question 9

What gene transcriptions are upregulated by Thazolinediones?

Answer 9

1) GLUT4 in skeletal muscle and adipose tissue

2) Adiponectin (increases number of fat cells responsive to insulin, increases fatty acid oxidation)

Question 10

Which drugs inhibit thyroid peroxidase?

Answer 10

Thionamide drugs- Propylthiouracil and Methimazole

Question 11

Which drug decreases peripheral conversion of T4 to T3?

Answer 11

Propylthiouracil

Question 12

Which drugs inhibit the sodium-iodide symporter in the thyroid?

Answer 12

Perchlorate and pertechnetate

Question 13

What is the action of SGLT2 inhibitors (canagliflozin and dapagliflozin)?

Answer 13

Act on SGL2, which is responsible for 90% of the glucose reabsorption in the proximal tubule. Contraindicated in those with renal disease

Question 14

What are the differences between hexokinase and glucokinase? Which is associated with MODY?

Answer 14

see page 86. Glucokinase

Question 15

What cells in the thyroid are derived from the neural crest? in the adrenal medulla?

Answer 15

Parafollicular c cells
Chromaffin cells

MOTEL PASS

Question 16

Why does anorexia cause amenorrhea?

Answer 16

Decreased leptin levels lead to inhibition of GnRH release from the hypothalamus

Question 17

Where are craniopharyngiomas and from what tissue are they derived?

Answer 17

suprasellar region. Rathke’s pouch remnant in the diencephalon. Have three components: solid, cystic, and calcification. Can lead to hypopituitarism and compression of the pituitary stock–>loss of dopaminergic inhibition of prolactin release

Question 18

What is Sheehan syndrome?

Answer 18

Ischemic necrosis of the pituitary gland due to peripartum hemorrhage (during pregnancy, pituitary enlarges, but blood supply does not)

Question 19

Which aromatase inhibitors are used in ER positive breast cancers?

Answer 19

anastrozole, letrozole, exemestane

Question 20

Why does brown fat create more heat?

Answer 20

Electron transport and phosphorylation are uncoupled leading to heat being generated instead of ATP

Question 21

How does epinephrine increase blood glucose?

Answer 21

glycogenolysis and gluconeogenesis in liver, skeletal muscle has decreased uptake of glucose and release of alanine (for gluconeogenesis by liver)