Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharm + Thera > Endocrine Pharmacology Thyroid > Flashcards

Endocrine Pharmacology Thyroid Flashcards

1
Q

Where does the thyroid sit and what is the functional unit

A

Follicles;

Thyroid hormones:

Iodine-containing amino acids
-thyroxine (T4)
-Triiodothyronie (T3)
-Thyroglobulin (Tg)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

H-P-T axis

A

hypothalamic (TRH)-pituitary(TSH)-thyroid axis(T4+T3)

Tissues: nuclear and membrane receptors: T4 is converted to T3

Liver:conjugation/excretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how is T3 and T4 made and what are they converted to

A

Enzymes add iodine to thyroglobulin to make it. (TPO); organification: iodide is converted to iodine and added to TG

most t3 comes from conversion at tissue site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Thyroid Hormones; where does it come from, how is it moved

A

-The iodine necessary for synthesis for thyroid hormones

comes from food/ supplements. Sea salts do not contain iodide

-Iodine is converted to iodide in the gut

-iodide is an active process and highly concentrated in the thyroid gland

-iodide is organified in the colloid of the follicle; the addition of iodide to TG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is iodide active transport is mediated by and what does it do

A

sodium-iodide symporter (NIS)

-NIS is a membrane protein that mediates active iodide uptake by the thyroid

-It is a specialized system that assures that adequate dietary I- accumulates in the follicles and becomes available for T4 and T3 biosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

T3 + T4 potency and where they are mostly at

A

T3 is 10x more potent than T4

-t4 is solely from the thyroid

-t3 is 20% from thyroid and 80% peripheral deiodination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does I get oxidized

A

I must be oxidized to iodinate Tyrosyl reidues of Tg

Iodination of the tyrosyl residues than forms monoidotyrosine (MIT) and diiodotyrosine (DIT) which are coupled to form T4 primarily or T3

-Reactions are catalyzed by Thyroid peroxidase (TPO)

TPO uses H2O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Drugs and conditions that increase T4 and T3 by increasing TBG

A

Drugs: oral contraceptives and other sorces of estrogen, methadone, heroin, clofibrate

Conditions: pregnancy, infectious/chronic active hepatitis, HIV infection, genetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Thyroid functions + pathophysiology

A

-essential for normal brain development and growth

-Critical for sexual maturation

Pathophysiology: metabolic disorders, hypo/hyperthyroidism, autoimmune disease and cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Thyroid hormone receptor and what it does and its implications

A

thyroid hormone receptor beta (TRB) is a tumor suppressor in thyroid, breast and others

TRB also promotes myelinization

Implications: multiple sclerosis; repair potential following brain and spinal cord injury; treatments for metabolic disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Thyroid hormone and metabolic activities

A

Thyroid hormones (T3) regulate of overall body metabolism
-T3 increases basal metabolic rate

Calorigenic effects
-T3 increases oxygen consumption in most peripheral tissues
-Increases body heat production

Metabolic effects:
-Stimulates lypolysis, and cholesterol metabolism; stimulates rapid removal of LDL, and stimulates carbohydrate metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many develop thyroid issues and who is more susceptible

A

12% of US population

-women are 5-8x more likely than men

thyroid cancer: 3-5% and increasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is hypothyroidism and what does it mean, how is it caused

A

it is a disorder where the thyroid fails to secrete an adequate amount of thyroid hormones

-most common thyroid disorder

Cause: primary thyroid gland failure; diminished stimulation of the thyroid gland by TSH…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Hashimoto and what does it mean and what do people present with, commonly associated with…

A

chronic autoimmune disease… occurs when there is a severe defect in the thyroid hormone synthesis

-characterized by destruction of the thyroid glad by autoantibodies against thyroglobulin, thyroperoxidase, and other thyroid tissue components

Present with: hypothyroidism, painless goiter, and other overt signs

Associated with: type 1 diabetes, autoimmune with other autoimmune diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hyperthyroidism

A

excess synthesis and secretion of thyroid hormones by the thyroid gland, which results in accelerated metabolism in peripheral tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hyperthyroidism underlying causes

A

Causes: toxic diffuse goiter (graves disease)
-toxic uniodular or multinodular goiter
-painful subacute thyroiditis
-silent thyroiditis
-toxic adenoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Graves disease (Toxic diffuse goiter)

A

Most common cause of hyperthyroidism
-60-90% of cases
-females more than males
-possibly related to defect in immune tolerance

-high levels of thyroid hormones, T4 and T3 will cause decrease in pituitary TSH levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Thyroid Nodular Disease

A

Thyroid gland nodules are common in the general population

-palpable nodules= 5% mainly in women

-most are benign, 8-10% with nodules have thyroid cancer

19
Q

What are the symptoms of goiter/disease

A

most are asymptomatic; they may be toxic or nontoxic

20
Q

What drugs are used in the treatment of hypothyroidism

A

Triiodothyronie (T3) and levothryoxine (T4)

Levothyroxine is used in most cases

21
Q

Compare and contrast Triiodothyronine and levothyroxine

A

levothyoxine : T4 is used for replacement and supression therapy, it is stable and has a long half-life (7 day) which permits once-daily administration. T4 is used to convert t3 in the body

Triiodothyronie: faster acting, shorter half life, and costs more than T4

22
Q

What is a drug that has both T3 and T4?

A

liotrix; it is an oral mixture of the two synthetic hormones in a 4-1 ratio by weight

23
Q

What are the classifications for drugs used to treat hyperthyroidism

A

Thioamides: hormone synthesis inhibitors

Iodides: hormone release inhibitors

Glandular destruction with radioactive iodine or surgery

inhibit ionic trapping

24
Q

What are some antithyroid drugs and what do they do

A

Thioamines, propylthiouracil (half-life of 1.5) , and methimazole (half-life of 6 hours)

They: are rapidly absorbed, reaching peak serum levels after 1 hour

Adverse effects: reactions occur in 3-12% of patients with a rash and fever being most common. Agranulocytosis (reversible)(low wbc count)

Thioamides accumulate in the thyroid- so plasma half-life does not affect the duration of action

Most important effect: block iodination of tyrosine residues of thyroglobulin

onset of action is flow- because synthesis not release

25
Q

What are iodides and what kind of drugs do they produce + what are some disadvantages +what happens with chronic use + how does autoimmune thyroid diseases (ex. graves) impact treatment?

A

antithyroid drugs; major action= inhibit hormone release

Rapid improvement with iodide treatment is used for “thyroid storm”

disadvantages: increase in iodine stores which may slow onset of thioamide action, fails to work after initial treatment period (Wolff-chaikoff effect)

Chronic use: hypothyroidism, goiter, salivary gland inflammation

Autoimmune thyroid diseases like graces means there is autoregulation of iodine and greater sensitivity so it is more effective

26
Q

What is thyroid storm and what are symptoms

A

also called thyrotoxic crisis happens when there is a large release of thyroid hormone in a short amount of time. rare complication of hyperthyroidism.. threatening

symptoms: rapid heartbeat, high temp, high BP (hypertension), yellowing of skin and eyes (jaundice), severe agitation and confusion, loss of consciousness

27
Q

What is radioactive iodine classified as and what is it used for + half life + adverse effects

A

131I is used ONLY for treatment of thyrotoxicosis

it is a Beta emitter, with half-life of 5 days and penetration range of 400-2000

Adverse reactions: genetic damage, leukemia, thyroid cancer, damage to fetal thyroid

28
Q

what are some Ionic inhibitors and what they do +adverse effects

A

-perchlorate blocks iodide from entering thyroid at the NIS symporter

-thiocyanate

Adverse effects: serious toxicity

29
Q

What are beta blockers and what do they do

A

They do not inhibit the production of thyroid hormones but they block the effects of hormones on the body

may provide rapid relief to irregular heartbeats, tremors, anxiety or irritability, heat intolerance, sweating, diarrhea and muscle weakness

30
Q

Thyroid hormone receptors and the treatment of other diseases

A

-Thyroid hormone receptor alpha predominantly in cardiovascular and brain
-Thyroid hormone receptor beta predominantly in liver
-thyroid receptor beta is a tumor suppressor in a multitude of tissues

31
Q

How prevalent is thyroid cancer

A

-most common endocrine cancer

-incidence increasing

-both large and microcarcinomas, better detction, enviro + lifestyle factors

4x more likley in women than men

-invasive, lethal tumor

32
Q

What are some risk factors for thyroid cancer

A

radiation exposure, gender/age, thyroid disease, diet/obesity, genetic mutations, environmental factors

33
Q

endocrine disruptors

A

-perchlorate (propellant)
-bisphenol A BPA (plastics, polycarbonates)
-flame retardants: PBDEs derivatives
-flooring, cosmetics
-PFOA/PFOS…C8 (non-stick coating)
-DDT, DDE (pesticides, breakdown products)
-synthetic estrogen (Pharmaceuticals)

34
Q

endocrine disrupting chemicals with their impacts on health

A

-little evidence to prove exposures cause health impacts but…

-increases in thyroid cancer; relationship to other cancers

  • Disruption of thyroid system; neurodevelopmental changes; metabolic changes

-declines in male/female fertility
-abnormalities in M/F reproductive organs
-increases in immune/autoimmune diseases, and some neurodegenerative diseases

35
Q

What are some Key Public health concerns

A

-increase in endocrine-related disorders in humans

-age

-latency effect (exposure early with disease outcome later)

-dose response (low level in environ… but doses at critical developmental stages in life)

-transgenerational effects (EDC exposure… epigenomic +genomic effects)

-Mixtures of chemicals and continued exposure

36
Q

The thyroid is… a what for environmental EDCs

A

a target…

BPA, phthalates, and perchlorate is also associated

-higher EDC concentrations in umbilical cord blood or urine from pregnant women is associated w/ poorer performance on cognition + neurobehavior

37
Q

what is perchlorate and what does it do

A

Perchlorate blocks radioactive iodine uptake (RUI)

REMEMBER: Iodine is essential for the synthesis of thyroid hormones; without iodine… low TH, high TSH, goiter, higher risk of developmental and metabolic disease and cancer

38
Q

What does BPA do

A

inhibits TR-mediated transcription and TH mediated phenotypic changes (metamorphosis)-

39
Q

Thyroid and infants

A

newborns have no thyroid hormone

-develop TH faster

-sensitive to small reductions in TH

-permanent effects from Th inefficiency

39
Q

Hyperthyroidism-thyrotoxicosis… state summary info

A

Too much TH

Graves’ disease: autoimmune
Toxic nodular goiter
Excessive intake of iodine
“Thyroid storm” is an extreme hyperthyroidism (e.g. infections, pregnancy, cardiac emergencies)

40
Q

Hypothyroidism

A

Not enough TH

Hashimoto’s thyroiditis: autoimmune
Postpartum thyroiditis

41
Q

Benign thyroid disease

A

Goiter-iodine insufficiency

42
Q

Thyroid cancer

A

Increasing 5%/year: papillary, follicular, anaplastic, medullary

Pharm + Thera (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions