Pituitary Hormones

Question 1

Growth hormone is also known as what?

Answer 1

somatotropin (do NOT confuse with somatostatin)

Question 2

Growth hormone is a ______ polypeptide.

Answer 2

single chain

Question 3

There is a growth spurt of what hormone at puberty?

Answer 3

growth hormone

Question 4

What hormone decreases with age?

Answer 4

growth hormone

Question 5

Growth hormone secretion is what pattern?

Answer 5

pulsatile

Question 6

What are the stimulators of growth hormone?

Answer 6

• Growth hormone releasing hormone
• decreased glucose
• decreased free fatty acids
• increased amino acids
• hypoglycemia/fasting/starvation
• puberty (estrogen/testosterone)

Question 7

What factors are included in the nutrient regulation of growth hormone?

Answer 7

• decreased glucose
• decreased free fatty acids
• increased amino acids

Question 8

What are the inhibitors of growth hormone?

Answer 8

• somatostatin
• increased glucose, free fatty acids
• growth hormone
• obesity
• somatomedins (Insulin like growth factors)

Question 9

What are somatomedins?

Answer 9

produced by liver, stimulate somatostatin release from hypothalamus, inhibit it at anterior pituitary, includes insulin like growth factors

Question 10

Growth hormone has metabolic actions on what structures?

Answer 10

• liver
• muscle
• adipose
• bone

Question 11

Growth hormone affects what?

Answer 11

• linear growth
• protein synthesis
• organ growth
• carbohydrate and lipid metabolism

Question 12

What are the direct anabolic actions of growth hormone?

Answer 12

increased Ca absorption from gut, P reabsorption from kidney, protein synthesis in liver

Question 13

Growth hormone has indirect metabolic actions via?

Answer 13

somatomedins

Question 14

What somatomedins cause the indirect actions of growth hormone?

Answer 14

IGF-1 (somatomedin C)
IGF-2 (somatomedin A)

Question 15

What are the indirect anabolic actions of growth hormone?

Answer 15

increased lean muscle mass, linear bone growth, organ size/function

Question 16

What are the direct catabolic effects of growth hormone?

Answer 16

• increased gluconeogensis in liver
• increased lipolysis in adipose tissue

Question 17

Increased gluconeogensis in liver by growth hormone causes what?

Answer 17

decreases glucose uptake in muscle which leads to temporary insulin resistance (maintenance of blood glucose)

Question 18

When free fatty acids are released into blood they bind what protein to become non-esterified fatty acids?

Answer 18

albumin

Question 19

A deficiency of growth hormone leads to what condition?

Answer 19

dwarfism

Question 20

Excessive growth hormone secretion leads to what condition?

Answer 20

acromegaly

Question 21

What hormones are released from the posterior pituitary?

Answer 21

• antidiuretic hormone
• oxytocin

Question 22

Which posterior pituitary hormone is synthesized primarily by neurons in supraoptic nuclei of hypothalamus?

Answer 22

antidiuretic hormone

Question 23

Which posterior pituitary hormone is synthesized primarily by neurons in paraventricular nuclei of hypothalamus?

Answer 23

oxytocin

Question 24

What is the peptide precursor of ADH?

Answer 24

prepropressophysin

Question 25

What is the peptide precursor of oxytocin?

Answer 25

prepro-oxyphysin

Question 26

When oxytocin is secreted due to stimulation by suckling, what results?

Answer 26

milk let down

Question 27

When oxytocin in secreted due to stimulation of cervix by fetus, what results?

Answer 27

uterine contractions

Question 28

What sensory receptors are responsible for suckling stimulation?

Answer 28

sensory receptors on myoepithlial cells of alveoli in mammary gland

Question 29

Oxytocin acts on what muscle in the uterus?

Answer 29

smooth muscle

Question 30

Oxytocin acts on what male reproductive structures to aid in sperm movement and ejaculation?

Answer 30

- testes - epididymis - prostate

Question 31

What are the stimulators of ADH secretion?

Answer 31

- increased plasma osmolarity - decreased blood volume (hypovolemia) - decreased blood pressure - pain - nausea/vomiting - hypoglycemia - nicotine, opiates

Question 32

What are the inhibitors of ADH secretion?

Answer 32

- decreased plasma osmolarity - increased blood volume (hypervolemia) - increased blood pressure - ethanol - glucocorticoids

Question 33

The secretion of ADH leads to the reabsorption of what?

Answer 33

water

Question 34

The inhibition of ADH means water is not reabsorbed, so it is excreted how?

Answer 34

excreted in urine

Question 35

Water is reabsorbed where in the nephron under the influence of AHD?

Answer 35

- distal convuluted tubule - collecting duct

Question 36

What are the two major actions of ADH?

Answer 36

- free water absorption in the kidney - vascular smooth muscle contraction

Question 37

Vascular smooth muscle contraction caused by ADH is done by what receptor?

Answer 37

V1 receptor

Question 38

Free water absorption by the kidney caused by ADH is done by what receptor?

Answer 38

V2 receptor

Question 39

How does ADH cause free water absorption in kidney?

Answer 39

increase water permeability of principal cells in distal convoluted tubules and collecting ducts of kidney by inserting aquaporin 2 into membrane of principal cells

Question 40

How does ADH cause vascular smooth muscle contraction?

Answer 40

constricts arterioles

Question 41

Abnormal ADH secretion can cause what two conditions?

Answer 41

- diabetes insipidus (lack of ADH if central, cells unresponsive to ADH if peripheral or nephrogenic) - syndrome of inappropriate ADH secretion (excess ADH)