Iodine Metabolism

Question 1

Iodine is abundant where?

Answer 1

sea, low on land

Question 2

how much iodine needed per day?

Answer 2

150ug

Question 3

Thyrotropin releasing hormone aka?

Answer 3

TRH

Question 4

Thyrotropin aka?

Answer 4

TSH

Question 5

Cretinism is?

Answer 5

maternal iodine deficiency causing congenitcal condition

Question 6

iodine-131 does what to thyroid?

Answer 6

destroy

Question 7

thyroid hormones operate via? act on?

Answer 7

• operate via membrane receptors

- direct activation of genes in DNA

Question 8

Iodine used externally as?

Answer 8

antiseptic

Question 9

Active form I2 is a?

Answer 9

potent oxidizer

Question 10

iodinated contrast avoided with who?

Answer 10

patients with possible thyroid carcinoma, interferes with post-operative radioactive iodine

Question 11

how much iodine do we have in our body?

Answer 11

20mg

Question 12

top 3 sources of iodine?

Answer 12

kelp
marine fish
shellfish

Question 13

upper limit for iodine per day?

Answer 13

1100ug/day

Question 14

What are goitrogens? examples?

Answer 14

inhibit iodide uptake:

soy, cabbage, kale, broccoli

Question 15

Cretinism preventable?

Answer 15

Yes, mothers need iodine

Question 16

iodine fortification in food include?

Answer 16

salt

bread

Question 17

Thyroid hormone alters energy levels via elevating?

Answer 17

ATP
Acetyl-CoA
NADH
NADPH
enzymes synthesis

Question 18

how much T4 and T3 % does thyroid make?

Answer 18

80% T4

20% T3

Question 19

precursor to T3 and T4?

Answer 19

tyrosine in the protein thyroglobulin

Question 20

condensations of DITs and MITs to form T3 and T4 catalysed by?

Answer 20

thyroperoxidase

Question 21

Half life of T4

T3?

Answer 21

T4: 6-9 days
T3: 24-36 hours

Question 22

what to do with excess iodine?

Answer 22

reverse T3 (3,3’,5): inactive to dump

Question 23

what is the uptaker for iodine?

Answer 23

NIS (Sodium/iodine symport)

Question 24

What drives the NIS for iodine uptake?

Answer 24

TSH-receptor activation and cAMP 2ndary messenger

Question 25

iodine-131 emits?

Answer 25

beta particles

Question 26

Propylthiouracil/methimazole inhibit what?

Answer 26

thyroperoxidase

Question 27

Grave's Disease does what?

Answer 27

auto-antibodies activated TSH receptor = +++Thyroid hormone

Question 28

T4 to T3 in liver happens how?

Answer 28

via Type 1 deiodinase

Question 29

T4 to T3 in brain happens how?

Answer 29

via type 2 deiodinase

Question 30

T4 to T3 in brown adipose, pituitary happens how?

Answer 30

within cells

Question 31

thyroid hormone receptors in DNA do what? what happens when T3 gets in?

Answer 31

usually repress | T3 takes away inhibition

Question 32

How long for T3 to produce an effect? lasts how long?

Answer 32

1-10 hours | lasts a few days

Question 33

hyperthyroidism symptoms?

Answer 33

``` difficulty sleeping heat intolerance infertility irritability muscle weakness nervousness scant menstrual periods ```

Question 34

hypothyroidism symptoms

Answer 34

``` arthritis cold intolerance depression dry skin fatigue forgetfulness heavy menstrual periods infertility muscle aches ```