Endocrine Physiology

Question 1

G-protein-coupled receptors:

GTP is stimulated by: _________ and inhibited by _________ and __________

Answer 1

Stimulated by Guanine nucleotide exchange factors (GEFs)

Inhibited by GTPase-accelerating proteins (GAPs) and RGS proteins (regulation of G protein signaling)

Question 2

Signal transduction systems used by all hypothalamic hormones except CRH:

Answer 2

IP3/DAG

Question 3

Signal transduction system used by:

ADH (V2 receptor: collecting duct of kidneys)

Answer 3

cAMP

Question 4

Signal transduction system used by:

ADH (V1 receptor: blood vessels)

Answer 4

IP3/DAG

Question 5

Signal transduction system used by:

Leptin, IGF-1, Insulin, EPO, GH, Prolactin

Answer 5

Tyrosine kinase

Question 6

Signal transduction system used by:

ANP, EDRF, nitric oxide

Answer 6

cGMP

Question 7

Signal transduction system used by:
Angiotensin II (epithelial cells)

Answer 7

cAMP

Question 8

Signal transduction system used by:
Angiotensin II (vascular smooth muscle)

Answer 8

IP3/DAG

Question 9

Signal transduction system used by:

Catecholamines (B1 and B2 receptors)

Answer 9

cAMP

Question 10

Signal transduction system used by:

Catecholamines (A1 receptors)

Answer 10

IP3/DAG

Question 11

Signal transduction system used by:

CRH

Answer 11

cAMP

Question 12

Signal transduction system used by:

Glucagon, Somatostatin, PTH, HCG, Calcitonin, ACTH, LH, FSH, TSH, secretin

Answer 12

cAMP

Question 13

Signal transduction system used by:

GnRH, TRH, GHRH, oxytocin

Answer 13

IP3/DAG

Question 14

Transport of steroid hormone

Answer 14

Bound to proteins

Question 15

Active form of steroid hormones

Answer 15

Free, unbound form

Question 16

Main site of inactivation of hormones

Answer 16

Liver

Question 17

Mechanism for removal of hormones

Answer 17

Liver, kidneys

Question 18

Number of hormone receptors - constant or variable?

Answer 18

Variable

Question 19

Minimum amount of hormone to produce effect

Answer 19

1 picogram per mL

Question 20

Onset of hormone effects

Answer 20

seconds to months

Question 21

What type of hormone interaction?

Epinephrine and NE on the heart

Answer 21

Synergistic, additive (simultaneous, same effect)

Question 22

What type of hormone interaction?

FSH and testosterone effects on spermatogenesis

Answer 22

Synergistic, complementary (different time, same effect)

Question 23

What type of hormone interaction?

Cortisol on Epinephrine and NE on blood vessels

Answer 23

Permissive

Question 24

What type of hormone interaction?

T3 on epinephrine on lipolysis

Answer 24

Permissive

Question 25

What type of hormone interaction? | Estrogen on prolactin effects on the breasts during pregnancy

Answer 25

Antagonistic

Question 26

Hormone has biologic actions that directly or indirectly inhibit further secretion of the hormone

Answer 26

Negative feedback

Question 27

Hormone has biologic actions that directly or indirectly stimulate further secretion of the hormone

Answer 27

Positive feedback

Question 28

Give an example of negative feedback that does not utilize the HPA:

Answer 28

Insulin

Question 29

Give 3 examples of positive feedback involving hormones:

Answer 29

1. Estrogen induced LH and FSH surge 2. Oxytocin during labor 3. Oxytocin during lactation

Question 30

Decrease in receptor number or receptor affinity by decreased synthesis, increased degradation or inactivation

Answer 30

Down-regulation

Question 31

Increase in receptor number or receptor affinity by increased synthesis, decreased degradation or inactivation

Answer 31

Up-regulation

Question 32

The pituitary gland lies in the sella turcica, and connected to the ______ of the hypothalamus via pituitary/hypophysial stalk

Answer 32

median eminence

Question 33

Transmit hypothalamic hormones to the pituitary without passing through the systemic circulation

Answer 33

Hypothalamic-hypophysial portal blood vessels

Question 34

The anterior pituitary is derived from the:

Answer 34

oral ectoderm (Rathke's pouch)

Question 35

FSH, LH, ACTH, TSH and MSH are what kind of cells?

Answer 35

basophilic cells

Question 36

GH and prolactin are what kind of cells?

Answer 36

acidophilic cells

Question 37

The posterior pituitary is derived from the:

Answer 37

neural ectoderm (neural outgrowth of the hypothalamus)

Question 38

Hormones from the posterior pituitary (pituicytes):

Answer 38

Vasopressin, oxytocin

Question 39

If the pituitary stalk is damaged, all anterior pituitary hormones would decrease, except:

Answer 39

Prolactin

Question 40

In terms of number, what are the top 2 cells in the anterior pituitary?

Answer 40

Somatotropes (40%), Corticotropes (20%)

Question 41

What are the "3 families" of hormones in the anterior pituitary?

Answer 41

TSH, LH, FSH (same alpha unit, unique beta unit) MSH, ACTH (derived from POMC) GH, Prolactin

Question 42

Growth hormone is release in pulsatile fashion every __ hours

Answer 42

2 hours

Question 43

Nocturnal peak of growth hormone is:

Answer 43

1 hour after stage 3 or 4 sleep

Question 44

Differentiate somatotropin from somatostatin from somatomedin

Answer 44

Somatotropin: growth hormone Somatostatin: stops growth hormone Somatomedin: IGF-1

Question 45

What are the direct actions of Growth hormone?

Answer 45

1. Increases blood glucose levels 2. Increased protein deposition in muscles and other tissue 3. Increased lipolysis 4. Increased IGF-1 production 5. Possible anti-aging effects

Question 46

What is the indirect action of growth hormone (via IGF-1)?

Answer 46

Increases bone length and bone thickness

Question 47

Secretion of growth hormone requires normal plasma levels of what hormone?

Answer 47

Thyroid hormone

Question 48

Achondroplasia is the most common cause of dwarfism. It is caused by a defect in:

Answer 48

FGF receptor 3

Question 49

Stimulates milk production by synthesis of lactose, casein, lipids; inhibits ovulation or spermatogenesis by decreasing GnRH; stimulates breast development during puberty and pregnancy

Answer 49

Prolactin

Question 50

What is one possible side effect of anti-psychotic drugs that involve prolactin?

Answer 50

Amenorrhea-Galactorrhea

Question 51

What stimulates prolactin?

Answer 51

Pregnancy (estrogen), breast feeding

Question 52

What inhibits prolactin?

Answer 52

Dopamine, bromocriptine