Endocrinology Basics I and II

Question 1

What are classes of the amine hormones?

Answer 1

Catecholamines
Indoleamines
Thyroid Hormones

Question 2

What are the monoamines?

Answer 2

Catecholamines

Indoleamines

Question 3

What is the half life of monoamines like?

Answer 3

VERY short (2-3 minutes)

Question 4

What is the half life of peptide hormones like?

Answer 4

Medium length (4-170 minutes)

Question 5

What is the half life of steroid like?

Answer 5

Long (minutes to hours)

Question 6

What are examples of catecholamines?

Answer 6

Dopamine
Norepinephrine
Epinephrine

Question 7

What is the precursor for catecholamines?

Answer 7

Tyrosine

Question 8

What is the enzyme for the rate limiting step for the formation of catecholamines?

Answer 8

Tyrosine Hydroxylase

Question 9

What is Tyrosine Hydroxylase activated by?

Answer 9

Sympathetic Activity

Question 10

What is Tyrosine Hydroxylase activated by?

Answer 10

Sympathetic Activity

Question 11

What are the main 2 organs that dopamine is made in?

Answer 11

Brain and Adrenal Gland

Question 12

What is the NT function of dopamine?

Answer 12

Activates reward pathways and is involved in attention and mood

Question 13

What is the hormone function of dopamine?

Answer 13

Inhibits prolactin release from the anterior pituitary

Question 14

What is the hormone function of dopamine?

Answer 14

Inhibits prolactin release from the anterior pituitary

Question 15

Where do dopaminergic neurons arise from?

Answer 15

Arcuate nucleus

Question 16

What converts dopamine into norepinephrine?

Answer 16

Dopamine Beta-hydroxylase

Question 17

Where is norepinephrine converted into epinephrine?

Answer 17

Adrenal Glands

Question 18

What is the enzyme for the rate limiting step for the formation of catecholamines?

Answer 18

Tyrosine Hydroxylase

Question 19

Where is norepinephrine converted into epinephrine?

Answer 19

Adrenal Glands

Question 20

What is the precursor for indoleamines?

Answer 20

Tryptophan

Question 21

What is the enzyme for the rate limiting step for the formation of indoleamines?

Answer 21

Tryptophan Hydroxylase

Question 22

What are examples of indoleamines?

Answer 22

Serotonin

Melatonin

Question 23

What is the function of serotonin in the brain?

Answer 23

It is the “happiness” hormone

Question 24

What is the function of serotonin in the body?

Answer 24

Serves as a vasoconstrictor and stimulates smooth muscle contraction

Question 25

What produces most of the serotonin in the body?

Answer 25

Enterochromaffin cells in the gut

Question 26

What is the function of drugs that act as selective serotonin reuptake inhibitors?

Answer 26

SSRIs work to increase the concentration of serotonin at the synaptic cleft and is used to treat depression. Causes negative feedback on serotonin synthesis.

Question 27

What is the main enzyme in monoamine metabolism?

Answer 27

Monoamine Oxidase

Question 28

What is measured in urine to determine the catecholamine levels?

Answer 28

VMA

Question 29

Where is melatonin made?

Answer 29

Pineal Gland

Question 30

How is melatonin made?

Answer 30

It is converted from tryptophan into serotonin into melatonin

Question 31

What is rate limiting step of melatonin synthesis?

Answer 31

N-acetyltransferase and it is the most active at night.

Question 32

What is melatonin and inhibitor of?

Answer 32

Potent inhibitor of reproduction

Question 33

What circadian rhythm is melatonin tied with?

Answer 33

Melatonin begins secretion during the dark. Duration of the dark period is important to get the full physiological effects of melatonin

Question 34

How are peptide hormones processed?

Answer 34

Peptide hormone is made as preprohormone and then the signal is cleaved which will form the prohormone. The pro hormone is the combination of the hormone and the copeptide.

Question 35

What is related with the half life of the hormone?

Answer 35

Size of the hormone is directly related to half life

Question 36

What are steroids derived from?

Answer 36

All derived from cholesterol precursor

Question 37

What is negative feedback?

Answer 37

A stimulates B which inhibits A

Question 38

What is positive feedback?

Answer 38

A stimulates B stimulates A

Question 39

What are the features of classical endocrine glands?

Answer 39

Ductless and secrete hormone directly into blood or extracellular space.

Question 40

What is the etiology and effect of cretinism?

Answer 40

It is a congenital deficiency caused by iodine deficiency during development that causes short stature/impaired bone formation, mental retardation and delayed motor development.

Question 41

What is the etiology and effect of multiple endocrine neoplasia?

Answer 41

It is a genetic disease caused by characterized by 2-3 tumors in multiple endocrine glands

Question 42

What is the most common endocrine disorder?

Answer 42

Diabetes Mellitus Type II

Question 43

What is endocrine signaling?

Answer 43

Hormones secreted into the blood acting on downstream target tissues.

Question 44

What is paracrine signaling?

Answer 44

Hormones secreted into the interstitial space acting at nearby cells.

Question 45

What is autocrine signaling?

Answer 45

Hormones secreted into the interstitial space acting back on same cell.

Question 46

What is the non-specific binding protein of hormones?

Answer 46

Albumin

Question 47

What are the 2 methods bound hormones are delivered to targets?

Answer 47

1. Steroid hormone is released at membrane and it freely diffuses across the lipid bilayer. 2. Hormone bound complex binds to megalin and and endocytic vesicle forms.

Question 48

What is the specificity of hormone:receptor binding?

Answer 48

It is the ability to distinguish between similar substances

Question 49

What is the affinity of hormone:receptor binding?

Answer 49

It is measured as Kd which is defined as the ligand concentration that occupies 50% of binding sites