Anterior Pituitary Hormones

Question 1

What is the role of somatotropin/GH?

Answer 1

Bone and Muscle Growth

Question 2

Where is GH produced?

Answer 2

By somatotrophs in the anterior pituitary gland

Question 3

GH is structurally similar to …

Answer 3

… prolactin

Question 4

What is IGF-1?

Answer 4

Molecules secreted in response to GH which mediate actions and regulation of GH

Question 5

What class of molecules are IGF-1?

Answer 5

Somatomedins

Question 6

What molecule is IGF-1 structurally similar to?

Answer 6

Insulin

Question 7

Is GH or IGF-1 measured for assessing GH deficiency?

Answer 7

IGF-1 is measured since they do not fluctuate through the day

Question 8

Which cells are signalled to grow after IGF-1 secretion?

Answer 8

Cells with adequate nutrients undergo hyperplasia and hypertrophy

Question 9

What effect do IGF-1 and GH have on bone growth in children?

Answer 9

Stimulate linear bone growth at the epiphyseal plate

Question 10

How do IGF-1 and GH affect muscle growth?

Answer 10

Stimulate myocyte hypertrophy
Increase protein synthesis

Question 11

What effect do GH and IGF-1 have on blood glucose concentrations?

Answer 11

Increase serum glucose

Question 12

How do GH and IGF-1 increase serum glucose concentration?

Answer 12

Increase hepatic gluconeogenesis
Increase lipolysis and lipid oxidation
Antagonize the action of insulin

Question 13

What factors may increase GH levels?

Answer 13

Sleep
Hypoglycemia
Stress
Increased ghrelin levels

Question 14

What factors may decrease GH levels?

Answer 14

Aging
Obesity
Glucose

Question 15

What is dwarfism?

Answer 15

Generalized deficiency of anterior pituitary hormone secretion

Question 16

What is a characteristic of dwarfism during puberty?

Answer 16

Does not reach puberty due to gonadotropin deficiency

Question 17

What are potential causes of dwarfism?

Answer 17

GH deficiency
Inability to form somatomedin C

Question 18

What is gigantism?

Answer 18

Excess GH secretion before puberty

Question 19

What is a potential cause of gigantism?

Answer 19

Tumors in anterior pituitary at GH secreting centers

Question 20

What are potential side-effects of gigantism?

Answer 20

Hyperglycemia

Question 21

What is acromegaly?

Answer 21

Excess GH after puberty

Because GH is secreted after puberty, the person cannot grow taller

Question 22

What are the signs of acromegaly?

Answer 22

Bones of hands, feet, cranium, supra orbital ridges, nose, vertebrae, jaw grow
Kidney, lungs and tongue increase in size

Kyphosis (Hunching of the back) is caused by increased growth of vertebrae

Question 23

Functions of prolactin

Answer 23

Milk production + Mammary Gland Development
Enhances maternal nurturing behaviours (cuddling, protection, grooming)
Reproduction
Nerve Formation
Fetal Development

Question 24

Where is prolactin produced?

Answer 24

Lactotrophs in the anterior pituitary gland
Also produced at extra-pituitary sites

Question 25

Which tissues are affected by prolactin?

Answer 25

Breast Pituitary Indirect influence of gonads

Question 26

What impact does prolactin have on sex hormones?

Answer 26

Depresses sex hormones (estrogen and testosterone)

Question 27

Relation between prolactin and autoimmunity

Answer 27

Prolactin suppresses negative selection of B cells Makes immune system more likely to attack native cells Causes higher incidence of autoimmune diseases in childbearing age women and postpartum women

Question 28

Positive regulators of prolactin secretion

Answer 28

Nipple stimulation Estrogen Thyrotropin-releasing hormone

Question 29

Negative regulators of prolactin secretion

Answer 29

Dopamine Progesterone

Question 30

How does prolactin level effect sex hormone production?

Answer 30

Prolactin inhibits GnRH production GnRH production inhibits LH and FSH secretion

Question 31

How does dopamine reduce prolactin secretion?

Answer 31

Prolactin increases dopamine production in hypothalamus Dopamine inhibits prolactin

Question 32

How does progesterone reduce prolactin secretion?

Answer 32

Inhibits prolactin at level of peripheral receptor