Endocrine Physiology

Question 1

TRH stimulates which 2 hormones?

Answer 1

TSH, Prolactin

Question 2

Dopamine inhibits which hormone?

Answer 2

Prolactin

Question 3

CRH stimulates which 3 hormones?

Answer 3

ACTH, MSH, beta-endorphin

Question 4

GHRH stimulates which hormone?

Answer 4

GH, TSH

Question 5

GnRH stimulates which 2 hormones?

Answer 5

FSH, LH

Question 6

Prolactin inhibits which hormone?

Answer 6

GnRH

Question 7

How does prolactin inhibit ovulation in females and spermatogenesis in males?

Answer 7

By inhibiting GnRH synthesis and release

Question 8

How does prolactin inhibit its own secretion?

Answer 8

Increasing dopamine synthesis and secretion from the hypothalamus

Question 9

Does TRH inc/dec prolactin secretion?

Answer 9

Inc

Question 10

Bromocriptine is a _____ agonist that can be used in the treatment of _____.

Answer 10

Dopamine; prolactinoma

Question 11

Dopamine antagonists (antipsychotics) and _____ stimulate prolactin secretion.

Answer 11

Estrogens (OCPs, pregnancy)

Question 12

GH stimulates linear growth and muscle mass through _____ secretion.

Answer 12

IGF-1/somatostatin

Question 13

Does GH inc/dec insulin resistance?

Answer 13

Inc

Question 14

T/F: GH is release in pulses in response to GHRH and secretion is inc during exercise and sleep.

Answer 14

TRUE

Question 15

Excess secretion of GH causes _____ in adults or _____ in children.

Answer 15

Acromegaly; gigantism

Question 16

State whether mineralocorticoids, cortisol, sex hormones inc/dec in 17 alpha-hydroxylase deficiency.

Answer 16

Inc, dec, dec

Question 17

How does an XY with 17 alpha-hydroxylase deficiency present?

Answer 17

HTN, hypokalemia. Dec DHT leads to pseudohermaphroditism (variable, ambiguous genitalia; undescended testes)

Question 18

How does an XX with 17 alpha-hydroxylase deficiency present?

Answer 18

HTN, hypokalemia. Externally phenotypic female with normal internal sex organs, lacks secondary sex characteristics

Question 19

State whether mineralocorticoids, cortisol, sex hormones inc/dec in 21-hydroxylase deficiency.

Answer 19

Dec, dec, inc

Question 20

How does a patient with 21-hydroxylase deficiency present?

Answer 20

Hypotension, hyperkalemia, inc renin activity, volume depletion. Masculinization, leading to pseudohermaphroditism in females.

Question 21

State whether mineralocorticoids, cortisol, sex hormones inc/dec in 11 beta-hydroxylase deficiency.

Answer 21

Mineralocorticoids: dec aldosterone, inc deoxycorticosterone; dec; inc

Question 22

How does a patient with 11 beta-hydroxylase deficiency present?

Answer 22

HTN, masculinization

Question 23

T/F: All congenital adrenal enzyme deficiencies are characterized by an enlargement of both adrenal glands due to inc ACTH stimulation because of dec cortisol.

Answer 23

TRUE

Question 24

Name 5 functions of cortisol.

Answer 24

1) Maintains Blood pressure 2) Dec Bone formation 3) Anti-Inflammatory/Immunosuppressive 4) Inc Insulin resistance 5) Inc Gluconeogenesis (*Remember BBIIG mnemonic!)

Question 25

T/F: Chronic stress induces prolonged cortisol secretion.

Answer 25

TRUE

Question 26

PTH is made by the _____ cells of the _____.

Answer 26

Chief, parathyroid

Question 27

Does PTH inc/dec bone resorption of calcium and phosphate?

Answer 27

Inc

Question 28

Does PTH inc/dec kidney reabsorption of calcium in the distal convoluted tubule?

Answer 28

Inc

Question 29

Does PTH inc/dec reabsorption of phosphate in the proximal convoluted tubule?

Answer 29

Dec

Question 30

Does PTH inc/dec 1,25-(OH)2D3 (calcitriol) production by stimulating kidney 1alpha-hydroxylase?

Answer 30

Inc

Question 31

State whether PTH inc/dec the following: Serum Ca2+, serum (PO4)3-, urine (PO4)3-

Answer 31

Inc, dec, inc

Question 32

PTH increases the production of M-CSF and RANK-L in _____, stimulating _____.

Answer 32

Osteoblasts; osteoclasts

Question 33

A dec in serum Ca2+ will inc/dec PTH secretion.

Answer 33

Inc

Question 34

A dec in serum Mg2+ will inc/dec PTH secretion.

Answer 34

Inc

Question 35

A large dec in serum Mg2+ will inc/dec PTH secretion.

Answer 35

Dec

Question 36

What are some common causes of dec Mg2+?

Answer 36

Diarrhea, aminoglycosides, diuretics, alcohol abuse

Question 37

Vitamin D2/D3 is from sun exposure in skin while vitamin D2/D3 is ingested from plants.

Answer 37

D3; D2

Question 38

Vitamin D2 and D3 are both converted to 25-OH in the _____ and to 1,25-(OH)2 (active form) in the _____.

Answer 38

Liver; kidney

Question 39

Vitamin D inc/dec absorption of dietary Ca2+ and (PO4)3- and inc/dec bone resorption of Ca2+ and (PO4)3-

Answer 39

Inc; inc

Question 40

Inc/dec PTH, inc/dec Ca2+, and inc/dec (PO4)3- cause inc 1,25-(OH)2 production.

Answer 40

Inc, dec, dec

Question 41

Calcitonin is made by the _____ cells of the _____.

Answer 41

Parafollicular; thyroid

Question 42

What is calcitonin's function?

Answer 42

Dec bone resorption of calcium

Question 43

How is calcitonin regulated?

Answer 43

Inc in serum Ca2+ causes calcitonin secretion

Question 44

Name the hormones associated with the cAMP signaling pathway.

Answer 44

FSH, LH, ACTH, TSH, CRH, hCG, ADH (V2 receptor), MSH, PTH, calcitonin, GHRH, glucagon (*Remember FLAT ChAMP mnemonic!)

Question 45

Name the hormones associated with the cGMP signaling pathway.

Answer 45

ANP, NO (EDRF) (*Think vasodilators)

Question 46

Name the hormones associated with the IP3 signaling pathway.

Answer 46

GnRH, GHRH, Oxytocin, ADH (V1 receptor), TRH, histamine, angiotensin II, gastrin (*Remember GGOAT mnemonic!)

Question 47

Name the hormones associated with the steroid receptor signaling pathway.

Answer 47

Vitamin D, Estrogen, Testosterone, T3/T4, Cortisol, Aldosterone, Progesterone (*Remember VETTT CAP mnemonic)

Question 48

Name the hormones associated with the intrinsic tyrosine kinase signaling pathway.

Answer 48

Insulin, IGF-1, FGF, PDGF, EGF (*MAP kinase pathway, think growth factors)

Question 49

Name the hormones associated with the receptor-associated tyrosine kinase signaling pathway.

Answer 49

Prolactin, Immunomodulators (eg. Cytokines, IL-2, IL-6, IL-8, IFN), GH (*JAK/STAT pathway. Think acidophiles and cytokines. Remember PIG mnemonic!)

Question 50

Steroid hormones are lipophilic, so they must do what in order to increase their solubility?

Answer 50

Must circulate bound to specific binding globulins

Question 51

In men, how does an increase in sex hormone-binding globulin clinically present?

Answer 51

Gynecomastia (because free testosterone is lowered)

Question 52

In women, how does an decrease in sex hormone-binding globulin clinically present?

Answer 52

Hirsutism (because free testosterone is raised)

Question 53

What are the 4 B's of thyroid function?

Answer 53

Brain maturation, bone growth, beta-adrenergic effects, and increased basal metabolic rate

Question 54

_____ binds most T3 and T4 in the blood.

Answer 54

Thyroxine-binding globulin

Question 55

Thyroxine-binding globulin is inc/dec in pregnancy or OCP use and inc/dec in hepatic failure

Answer 55

Inc, dec

Question 56

Does T3 or T4 bind receptors with greater affinity?

Answer 56

T3

Question 57

What is the Wolff-Chaikoff effect?

Answer 57

Excess iodine temporarily inhibits thyroid peroxidase which leads to decreased iodine organification which leads to decreased T3 and T4 production

Question 58

What is the enzyme responsible for oxidation and organification of iodide as well as coupling of MIT and DIT?

Answer 58

Peroxidase

Question 59

What is the difference between propylthiouracil and methimazole?

Answer 59

Propylthiouracil inhibits both peroxidase and 5'-deiodinase while methimazole inhibits peroxidase only