L69: Endocrinology Basics (Part II) Flashcards Preview

FHB - Endocrinology (by Richie) > L69: Endocrinology Basics (Part II) > Flashcards

Flashcards in L69: Endocrinology Basics (Part II) Deck (41)
1

Where is serotonin converted into melatonin?

pineal gland

2

What is the basic building block of catecholamines

tyrosine

3

What is the basic building block of indolamines

tryptophan

4

What is the rate limiting step of catecholamine synthesis?

Tyrosine to X-dopa via TYROSINE HYDROXYLASE

5

What is the rate limiting step of indolamine synthesis?

Tryptophan to 5-HTP via TRYPTOPHAN HYDROXYLASE

6

What enzyme catalyzes norepinephrine synthesis, and where is it located?

Dopamine B-hydroxylase. Located in adrenal medulla.

7

What cells in the adrenal medulla are homologous to post-synaptic neurons?

Chromaffin cells

8

Entecapone & benzeride carbidopa

inhibit extracellular conversion of L-dopa to 3-OMD and dopamine, respectively

9

MAOA and MAOB inhibitors

prevent monoamine inactivation

10

SSRI

decrease uptake of 5-HT at synaptic cleft. May lead to desensitization of post-synaptic receptors and negative feedback.

11

N-acetyltransferase is the rate-limiting step for making which hormone?

Melatonin

12

4 examples of + feedback

1. partuition - childbirth 2. Lactation 3. Ovulation 4. Blood clotting (5. when your boss says good job)

13

4 examples of positive feedback

1. partuition - childbirth 2. Lactation 3. Ovulation 4. Blood clotting (5. when your boss says good job)

14

Hypothalamus. What level of axis is this?

Tertiary

15

Pituitary. What level of axis is this?

Secondary

16

Breasts, testes, thyroid. What level of axis is this?

Primary

17

Which has a longer half life: ANP or BNP?

BNP - thus its a useful diagnostic tool.

18

BMP. Higher in men or women?

Women

19

BMP. Increases or decreases with age?

increases

20

BMP. Higher with CHF and renal failure, or lower?

HIgher

21

Normal BMP. Rules out what?

CHF

22

Pt. has high baseline TSH. In response to TRH, TSH increases then returns to high baseline. Significance?

Primary failure at level of thyroid. Since thyroid isn't making T3/T4, then there is no negative feedback to stop pumping out TSH. 

23

Pt. has low baseline TSH that doesn't respond to TRH. Significance?

This means the patient cannot synthesize TSH normally; thus it makes sense he cannot increase TSH in response to TRH. This is indicative of a secondary failure at level of pituitary.

24

Pt. has a slightly higher baseline of TSH, with a protracted return to baseline upon TRH stimulation. Significance?

Tertiary problem at hypothalamus. Slower response to TSH (because pituitary not prepared to recieve TRH for once) and protracted return to baseline. 

25

Does age affect circulating hormone levels?

Yes

26

Factors that affect circulating hormone levels. Name 5

1. Age

2. Sex

3. Body weight

4. Time of day

5. Diet

27

NE acts at alpha or beta adrenergic receptors?

Both

28

Where does the conversion from NE to Epi occur?

adrenal medulla

29

95% of 5HT is made where

gut

30

inactivates and degrades catecholamines

COMT

31

What enzyme takes L-DOPA to dopamine?

Dopa decarboxylase (DDC)

32

catalyzes deamination of monoamines (eg. dopamine)

MAO

33

Which of the following enzymes is most active in the dark?

A. Tyrosine hydroxylase

B. Dopamine beta Hydroxylase

C. Trypophan hydroxylase

D. N-acetyltransferase (SNA)

D. N-acetyltransferase (SNA)

which is located in pineal gland and synthesizes melatonin from 5HT

34

Define preprohormone

Signal-hormone-copeptide

35

define prohormone

hormone-copeptide (no signal sequence)

36

Which of the following are packaged in the vesicle?

A. Signal peptide

B. Hormone

C. copeptide

D. Two of the above

D. 

Hormone and copeptide are packaged into vesicle

Eg. Insulin + C-peptide

37

Cholesterol to pregnenalone?

Desmolase (CYP11A1)

38

Corticosterone to aldosterone?

CYP11B2 - aldosterone synthase

39

11-DOC to corticosterone?

CYP11B2 - 11beta hydroxylase

40

progesterone to 11-DOC

CYP21A2 - 21 alpha hydroxylase

41

Steroid abusing body builders need to take _______ when they come off of testosterone.

hCG. This acts like LH. When you come off of T, negative regulation at hypothalamus is lifted, and pituitary starts secreting LH again, but we might need hCG initially to make the transition smoother.