Strumigeny mnou blíže nezařazené

2-mercaptobenzothiazole (MBT)

• Inhibited TPO activity [32]

3,5-dimethylpyrazole-1-methanol (DPM)

• Inhibited TPO activity [32]

3-methylchloranthracene

• Decreased TPO activity in vitro assay [26]

4-propoxyphenol (4POP)

• Inhibited TPO activity [32]

6-propylthiouracil (PTU)

• Inhibited TPO activity [32]

Amiodarone

• Inhibits peripheral conversion of thyroxine to triiodothyronine
• Interferes with thyroid hormone action [9]

AMK

• In vitro thyroid peroxidase (TPO) iodide oxidation activity

• Completely inhibited by:
• Hydrolyzed TPO preparation (0.15 mg/ml)
• Hydrolyzed bovine serum albumin (BSA, 0.2 mg/ml)
• Pancreatic hydrolysate of casein (trypticase peptone, 0.1 mg/ml)
• Cysteine, tryptophan and methionine, 50 µM each [16]

• Inhibited the TPO reaction by 54% or less
• Casamino acids (0.1 mg/ml)
• Tyrosine
• phenylalanine
• histidine (50 µM each) [16]

• Did not significantly decrease TPO activity:
• A pancreatic digest of gelatin (0.1 mg/ml)
• Other amino acid (50 µM) [16]

• Amino acids that impair iodide oxidation
• Also inhibit the TPO albumin iodination activity [16]

• Inhibitory amino acids
• Contain side chains with either
• Sulfur atoms (cysteine and methionine)
• Aromatic rings (tyrosine, tryptophan, histidine and phenylalanine) [16]

• Only cysteine affected the TPO guaiacol oxidation reaction
• Producing a transient inhibition at 25 or 50 µM [16]

• Iodide oxidation inhibitory activity of
• Cysteine
• methionine
• tryptophan [16]
• Was reversed by increasing iodide concentrations from 12 to 18 mM
• No such effect was observed when
• The cofactor (H2O2) concentration was increased [16]

• Inhibitory substances might interfere with the enzyme activity
• By competing with its
• Normal substrates for their binding sites
• Binding to the free substrates
• Reducing their oxidized form [16]

As2O3

• Binds to TPO's free sulfhydryl groups

Reduced glutathione (GSH)

• Inhibit TPO activity in vitro
• May occur because GSH acts as a competitive substrate for hydrogen peroxide
• Or possibly reduce the oxidized form of iodide
• Requirements for TPO action
• GSH is known to inhibit thyroid hormone synthesis
• Protecting the thyroid gland from oxidative damage induced by arsenic

Combination of As2O3 and reduced GSH

• As2O3 (0.01, 0.1, 1, and 10 ppm) - inhibit TPO activity
• GSH (0.1, 1, 5, and 10 ppm)
• 5 and 10 ppm GSH also inhibit TPO activity
• As2O3 (0.1 ppm) and GSH (0.01, 0.1, 1, or 10 ppm) combinations
• 0.1 ppm As2O3 (i.e., the lowest dose of arsenic able to partially inhibit TPO activity)
• Combined with 0.01, 0.1, 1.0, or 10 ppm GSH
• Inhibition of in vitro TPO activity is augmented
• Complete inhibition of TPO

Babassu (plody kokosové palmy populární v Brazílii a Africe)

Bacterial lipopolysaccharides

• Genetically exposed mice
• Shown to triggerautoimmune thyroiditis [10]

Bamboo shoots - BS

• Fresh contains
• High cyanogenic glucoside (551 mg/kg)
• Followed by thiocyanate (24mg/kg)
• Glucosinolate (9.57mg/kg)
• In vitro inhibition in TPO activity
• Found with raw
• Raw boiled
• Cooked extracts
• Inhibition constant (IC50) and PTU equivalence of fresh BS
• Were 27.5+/-0.77 microg and 3.27 respectively
• Extra iodide in the incubation media
• Reduced TPO inhibition induced by BS
• But could not cancel it
• BS fed animals for 45 and 90 days
• Significant increase in thyroid weight
• Higher excretion of thiocyanate and iodine
• Decrease in thyroid peroxidase activity, T4 and T3 levels
• Chronic BS consumption gradually developed a state of hypothyroidism

Benzhydrol

• Decreased TPO activity in vitro assay [26]

Benzo(e)pyrene

• Decreased TPO activity in vitro assay [26]

Benzo(k)fluoranthene

• Decreased TPO activity in vitro assay [26]

Benzophenone-2

• UV filters meant to protect skin from UV irradiation
• Can also alter thyroid homeostasis [10]
• Treated rats showed
• Low T4 levels
• High TSH levels
• Altered Thyroid-peroxidase activity [10]
• Interferes with the thyroid hormone axis in rats
• Is a potent in vitro inhibitor of human recombinant thyroid peroxidase [23]
• BP2 is contained in numerous cosmetics of daily use and may be in regular contact with human skin
• Half-maximal inhibition in the guaiacol assay occurred at 450 nmol/liter BP2
• A concentration 20- and 200-fold lower than those required in case of the TPO-inhibiting antithyroid drugs methimazole and propylthiouracil [23]
• BP2 at 300 nmol/liter combined with the TPO substrate H(2)O(2) (10 mumol/liter) inactivated hrTPO;
• This was, however, prevented by micromolar amounts of iodide [23]
• BP2 did not inhibit iodide uptake into FRTL-5 cells
• In BP2-treated rats (333 and 1000 mg/kg body weight)
• Serum total T(4) was significantly decreased
• Serum thyrotropin was significantly increased
• TPO activities in the thyroids of treated animals were unchanged
• Finding also described for methimazole and propylthiouracil [23]
• BP2, may disturb TH homeostasis
• By inhibiting or inactivating TPO
• Even more pronounced in the absence of iodide [23]

Benzophenone

• Decreased TPO activity in vitro assay [26]

Benzothiazole (BTZ)

• Potency for TPO inhibition was MBT=CMBT>ABT>BTZ [27]
• MBT and CMBT, produced responses in vivo
• T4 synthesis inhibition
• Induction of sodium iodide symporter mRNA
• Decreases in glandular and circulating thyroid hormones
• Results indicate that inhibition of TPO activity in vitro
• Was a good indicator of a chemical's potential for thyroid hormone disruption in vivo [27]

2-mercaptobenzothiazole (MBT)

5-chloro-2-mercaptobenzothiazole (CMBT)

2-aminobenzothiazole (ABT)

Bisphenol-A

• May have direct action on thyroid hormone receptor [10]

Bromine

• Genetically exposed mice
• Shown to triggerautoimmune thyroiditis [10]

Cassava root

Coal derivatives

• Resorcinol
• Phthalates
• Anthracenes [20]

Cyanogenic Plant Foods

• Raw, boiled and cooked extracts of various cyanogenic plant foods including:
• Cauliflower
• Cabbage
• Mustard
• Turnip
• Raddish
• Bamboo shoot
• Cassava
• Possess anti-TPO activity
• Boiled exracts of these cyanogenic plant foods
• Showed highest anti-TPO potency
• Followed by cooked and raw extracts [10]

Jaký je rozdíl mezi boiled a cooked ????

DDT

• DDT at doses of 1.89±0.86 ?g/kg/day and 7.77±0.17 ?g/kg/day for 6 and 10 weeks
• Dose dependent increase of serum total thyroxine, total triiodthyronine, and thyroid peroxidase
• Revealed after 6 weeks exposure
• After 10 weeks free thyroxine secretion was reduced
• Typical for iodine deficient goiter [30]
• Main mechanism of DDT action includes
• Disruption of thyroxine secretion by thyrocytes
• But not inhibition of deiodinase activity
• Decrease of blood thyroid binding proteins [30]

Dietary peanut seed coats (PSC)

• In animals, long-term feeding with peanut (Arachis hypogaea) seed coats
• Causes hypertrophy and hyperplasia of the thyroid gland
• High levels of pro-goitrogenic substances
• Phenolic
• Cyanogenic constituents
• Fed to rats for 30 and 60 days PSC-supplemented diet
• Significant increase in urinary excretion of thiocyanate and iodine
• Thyroid enlargement
• Hypertrophy and/or hyperplasia of thyroid follicles
• There was inhibition of
• Thyroid peroxidase (TPO) activity
• 5'-deiodinase-I (DIO1) activity
• (Na+-K+)-ATPase activity compared to controls
• Decreased serum circulating total T4 and T3 levels [28]

Diethylhexylphthalate (DEHP)

• Inhibited TPO activity [32]

Diethylphthalate (DEP)

• Inhibited TPO activity [32]

Ethylenethiourea (ETU)

• Thyroid carcinogen
• In foods formed by degradation and metabolism of ethylenebis[dithiocarbamate] fungicides
• ETU inhibits thyroid peroxidase (TPX)
• Inhibition of TPX-catalyzed reactions by ETU occurs only
• In the presence of iodide ion
• With concomitant oxidative metabolism to
• Imidazoline
• Bisulfite ion [17]
• Inhibition ceases upon consumption of ETU
• Low-level or intermittent exposure to ETU
• Would have minimal effects on thyroid hormone production [17]

Excess dietary iodine

• In genetically susceptible individuals
• Increased consumption of Iodine can act as a trigger for thyroiditis
• Iodine laden foods viz.
• Kelp seaweed,
• Iodinated salt,
• Iodine additives to bread /flour,
• Preservatives,
• Medicines such as amiodarone,
• Vitamins,
• Lugol’sIodine topical antiseptics
• Contrast dyes
• May act as starting point
• Highly iodinated thyroglobulin
• More immunogenic than poorly iodinated one [10]
• Iodine may also have a direct toxic effect on thyroid
• Via free oxygen radicals
• Immune stimulation [10]

Flavonoids

• More potent inhibition of TPO by the same mechanism as resorcinol and derivatives
• Fisetin
• Kaempferol
• Naringenin
• Quercetin [13]
• Noncompetitive inhibition of tyrosine iodination
• Myricetin
• Naringin
• Linear mixed-type inhibition
• Hydrogen peroxide [13]
• Alternate substrate for iodination
• Biochanin A
• Main product 6,8-diiodo-biochanin A [13]
• A 50% inhibition of TPO activity was obtained at
• 11 microM baicalein
• 13 microM quercetin
• 17 microM catechin
• 55 microM morin
• 68 microM rutin
• 70 microM fisetin
• 72 microM kaempferol
• 77 microM biochanin A [14]

Goitrin

• Active goitrogen present in plants of:
• Rutabaga
• Turnip
• Brassicae seeds
• Cooking destroys the enzyme responsible for activation of progoitrin to goitrin
• Negating its anti-thyroidal potency [10]
• Goitrogenic foods if consumed in considerable quantities
• May contribute to development of goiter
• Difficult to incriminate them as aetiologic factors in vast majority of goitrous patients [10]

Green Tea

• In response to dietary green tea extract in rats [10]
• Thyroid function can be impaired by green tea extracts at high doses
• Significant decrease in serum T3 and T4
• Increase in TSH levels
• Decreased TPO
• Decreased deiodinase activity
• Catechins in green tea in rat model study
• Decreased activity of thyroid peroxide
• Decreased 5’-deiodinaseI enzymes
• Decreased levels of serum T3 and T4
• Significant elevation of TSH [10]

Zelený čas stimuluje UCP1 tedy produkci tepla v MTCH na úkor produkce ATP a hormony štítné žlázy také, tak je asi dobře, že to tělo umí zkompenzovat, když si dám čaj, aby se tento účinek nestal fatálním... Zajímalo by mě, jak rychle po skončení zátěže catechiny se hladiny hormonů štítné žlázy vrátí k normě.

Vlastní zkušenost: První užití výtažků zeleného čaje - již po pár hodinách vzniknul hlad a pocit, že došlo k úbytku v tukové tkáni. Při dalším užití další dny tento efekt již nenastal. Za další dny bez výtažků byl člověk jaksi zpomalený, že jsem si pak i po nějaké době vzpomněla na to, že mi možná zase chybí hormon štítné žlázy a půl tabletky jsem si zase dala, abych byla mentálně použitelnější. Tak teď už aspoň vím proč to tak bylo.

Jsou známé případy, kdy lidi požili větší dávku výtažků z čaje a zemřeli na selhání jater - jaterní buňky asi neměly dost atp na svůj náročný metabolismus. Dokážu si představit, že toto riziko mohlo být potencováno zároveň užívanými hormony štítné žlázy.

Groundnut - podzemnice olejná

• Active principle arachidoside
• Groundnut supplements in albino rats
• Reported to be goitrogenic
• Effect was inhibited by small amounts of iodine as potassium iodide [10]

Halogenated phenolic compounds

• 25 halogenated phenolic compounds inhibited IYD (iodotyrosine deiodinase) activity
• At the concentration of 1×10(-4)M or 6×10(-4)M
• Halogenated compounds may disturb thyroid hormone homeostasis via inhibition of IYD
• Halogen atom and hydroxyl group substitution on a phenyl ring [31]

Rose bengal

• Was the most potent inhibitor [31]
• Followed by

Erythrosine B

Phloxine B

Benzbromarone

4'-hydroxy-2,2',4-tribromodiphenyl ether

4-hydroxy-2,3',3,4'-tetrabromodiphenyl ether

4-hydroxy-2',3,4',5,6'-pentachlorobiphenyl, 4'-hydroxy-2,2',4,5'-tetrabromodiphenyl ether

Triclosan

4-hydroxy-2,2',3,4',5-pentabromodiphenyl ether

Heavy fuel oil product (F-179)

• Two studies
• Thyroid inflammation at 10-55mg/kg
• Co-occurred with liver pathology in rats
• Polycyclic aromatic hydrocarbon (PAH) content was higher than in related substances
• Reduced thyroid peroxidase (TPO) activity with exposure to some PAH compounds
• Pyrene
• Benzo(k)fluoranthene
• Benzo(e)pyrene [25]

Hepatic deiodinase activities stimulovány

Heptachlor

• Decreased TPO activity in vitro assay [26]

Herbicides

• 60% of all herbicides
• 2,4-dichlorophenoxyacetic acid (2,4-D)
• Acetochlor
• Aminotriazole
• Amitrole
• Bromoxynil
• Pendamethalin
• Mancozeb
• Thioureas [20]

Horseradish

• Thirteen synthesized flavonoids as peroxidase inhibitors

IgG-class autoantibodies (TPOAb)

• Markers of thyroid in?ltration
• Implicated in thyroid destruction [15]

Insulin

• A cytosolic inhibitor of:
• Thyroid peroxidase (TPO)
• Lacto peroxidase (LPO)
• Horseradish peroxidase (HRPO)
• Glutathione peroxidase (GPX) [33]

• Insulin significantly
• Increases the concentration of the peroxidase inhibitor in a thyroid cell culture at 48 h

• The presence of insulin during 48 h
• Induces cell proliferation of the thyroid cell culture
• insulin stimulates thyroid cell division through the effect of a peroxidase inhibitor, as its second messenger [33]
• The inhibition of GPX by its action
• Positively modulates the H2O2 level
• Signal for cell proliferation [33]

Iopanoic acid (IOA)

• Inhibited TPO activity [32]

Iopanoic acid

Isoflavones

• Reduce thyroperoxidase activity [10]

Jet fuel product (JP-8)

• JP-8 product differs from other fuels
• Presence of additives
• Reduced T4 levels in mice in the study
• At a dose above that expected to occur in environmental settings (e.g. 2000mg/kg) [25]

Dietary high–fat lard intake (Sádlo - špek)

• Induced in rats
• Significant thyroid dysfunction
• Abnormal morphology
• Failed to be corrected by short-term dietary modification
• Raised triglyceride levels
• Decreased total T4 and free T4 levels
• Raised serum TSH [10]

Legumes

Leishmaniasis

Lithium

M. uniflora

• Aqueous partition of the methanolic extract of M. uniflora
• Able to inhibit TPO activity in vitro
• Mearnsitrin
• Myricitrin
• Degree of TPO inhibition produced by the aqueous solution of the flavonoids was very high
• 50% inhibition of the original TPO activity
• At 1.97 microM mearnsitrin
• At 2.88 microM myricitrin
• Indiscriminated consumption of M. uniflora pharmaceutical products
• Allied to the nutritional deficiency of iodine
• Might contribute to the development of hypothyroidism and goiter

Malachite green (MG)

• Used to treat and prevent fungal and parasitic infections in the aquaculture industry
• Reduced metabolite of MG, leucomalachite green (LMG)
• Accumulates in the tissues of fish
• Structurally related to other triphenylmethane dyes (e.g., gentian violet and pararosaniline)
• Is carcinogenic in the liver, thyroid, and other organs of experimental animals [15]
• LMG
• Inhibit thyroid peroxidase (TPO)
• Half-maximal inhibition at ca. 10 microM [15]
• Increased serum thyroid-stimulating hormone and decreased serum thyroxine in rats treated with LMG
• Chronic exposure could cause thyroid follicular cell tumors [15]

Maniok (kasava)

• Epidemiologie strumy v Africe a Asii je spojena s konzumací manioku
• Bohatého na kyanogenní glykosid linamarin
• Goiter and IDDs have also been attributed to cassava consumption in many parts of the underdeveloped world
• Cassava is a widely grown root crop
• Accumulates cyanogenic glucosides
• Linamarin
• Amygdalin
• Lotaustralin
• Linamarin accounts for more than 80% of the cassava cyanogenic glucosides
• Cyanide intoxication can occur when poorly processed cassava meal is eaten

Mercury

• Mercury is a well known antithyroid substance
• Causing inhibition of
• Deiodinases
• Thyroid peroxidase [20]

Millet - proso - jáhly

• Pearl millet (Pennisetum glaucum)
• Fonio millet (Digitaria exilis)
• Various studies on rats and thyroid slices of pork
• Millet diets
• Containing C-glycosylflavones
• Glycosylvitexin
• Glycosylorientin
• Vitexin
• Produce effects resembling small doses of anti-thyroid drug, methimazole
• Millet bran fraction having maximum concentration C-glycosylflavones:
• Maximum anti-thyroid effect
• Significant increase in thyroid weight
• Maximum inhibition of TPO activity [10]

MMI, PTU, MBT, DPM, 4POP

• Inhibited TPO activity [32]

Nitrates

• Interfere with iodine uptake [10]

OMC - Octyl-methoxycinnamate

• Dose dependent decrease in serum T3 and T4 concentration in rats [10]

Cadmium

• Affect thyroid function

Lead

• Affect thyroid function
• Lead exposed cows living in polluted areas showed
• Significantly higher blood lead and T3, T4 concentration [10]
• Study on pregnant women from lead exposed town
• Lower mean free thyroxine (FT4)
• Higher mean TPO antibodies
• Higher lead concentration
• Suggesting stimulation of auto-immunity by prolonged lead exposure [10]

Organochlorine compounds found in pesticides

• Induce hepatic enzymes
• Leading to decreased half-life of serum thyroxine (T4) [10]

Raw foods

• Lightly goitrogenic raw food food:
• (cooking inactivates some kindes of goitrogens)

• Cassava
• Soybeans
• Tofu
• Soybean oil
• Soy flour
• Soy lecithin
• Strumy u dětí na “sójovém mléku”
• Doporučilo se sójové mléko obohacovat jódem
• Pravděpodobně se koncentrují hlavně v tofu (“sójovém tvarohu”)
• Strumigenní aktivita i v menší míře i v restované sójové mouce, koncentrátech a izolátech [7]
• Pine nuts
• Peanuts
• Millet
• Strawberries
• Pears
• Peaches
• Spinach
• Bamboo shoots
• Sweet Potatoes
• Kasava - maniok [7]
• Proso (jáhly, čirok) [7]
• Babassu (plody kokosové palmy populární v Brazílii a Africe)

Some oxazolidines - goitrin

P-nonylphenol (PNP)

• Inhibited TPO activity [32]

Některá perorální antidiabetika

Perchlorates

• Found in rocket fuels
• Interfere with iodine uptake [10]
• Pregnant women living in an industrial area in south California
• Strong association between
• Increased urinary perchlorate
• Decreased total and free thyroxine levels
• Increased TSH levels [10]
• Iodine uptake inhibition and any potential downstream effect by perchlorate are highly dependent on the presence of other environmental NIS inhibitors and iodine intake itself.

  www.ncbi.nlm.nih.gov/pubmed/16793945

• Known competitive inhibitor of the sodium/iodide symporter (NIS)
• Environmental perchlorate in the US
• (RfD) of 0.0007 mg/kg per day in drinking water

Perfluorooctane sulfonate (PFOS)

• Decreased TPO activity in vitro assay [26]

Perfluorooctanoic acid (PFOA)

• Decreased TPO activity in vitro assay [26]

Petroleum streams

• Three rodent studies did find thyroid effects
• Few products may carry a weak potential to affect the thyroid at high doses in rodents
• Human epidemiology evidence found weak and inconsistent effects on the thyroid
• Without identification of specific chemicals involved [25]
• Two studies in petroleum workers
• Reported a statistically significant increase in thyroid cancer [25]

Polybrominated diphenyl ethers (PBDEs)

• May have direct action on thyroid hormone receptor [10]
• Increase flame resistance in consumer goods
• These compounds and their hydroxylated derivatives (OH-BDEs) impair normal thyroid function

Polychlorinated biphenyls (PCBs)

Polychlorinated biphenyls

• May have direct action on thyroid hormone receptor [10]

Polyunsaturated fats

• Decrease in Tri-iodothyronine and thyroid peroxidase levels in rats [10]

Potassium perchlorate

• Decrease iodide uptake by competitive inhibition
• Reduces thyroxine and triiodothyronine secretion
• Increased release of thyrotropin (reduced negative feedback)
• Stimulates the gland [9]

Propylthiouracil

Proso (jáhly, čirok)

• Epidemiologie strumy v Africe a Asii je spojena s konzumací prosa
• Obsahuje goitrogenní flavonoid vitexin

Pyrene

• Decreased TPO activity in vitro assay [26]

Ropylthiouracil

Selenium deficiency

• Implicated in autoimmune thyroiditis [10]

Smoking

• Third National Health and Nutrition Examination Survey (NHANESIII)
• Relationship between smoking and thyroid abnormalities was evaluated
• Smoking inversely related to the prevalence of serum thyroid auto-antibodies
• Lesser number of smokers
• Serum thyroid auto-antibodies (11%)
• Elevated TSH (2.6%)
• Non-smokers
• Auto-antibodies (18%)
• Elevated TSH (5.5%) [10]

Sodium perchlorate (PERC)

• Inhibited TPO activity [32]

Soja

• Soy or soy enriched foods
• Can also aggravate thyroid problems
• Reducing T4 absorption
• Interfering with thyroid hormone action
• Increase auto-immune thyroid disease [10]
• Development of goiter and hypothyroidism in a 10-month-old infant
• Who was put on soybean product right from birth
• It reversed with
• Soybean product withdrawal
• Lugol’s iodine drops [10]
• Thyroid showed high uptake of I131 after soybean product withdrawal
• Studies on adults
• Revealed significant suppression in plasma-bound I131 while receiving soybean product
• Soybean product
• Seemed to contain goitrogenic agent which affects thyroid function [10]
• 14 trials concluded that although soya protein and isoflavones
• Do not affect normal thyroid function in people with sufficient iodine intake
• But they may interfere with
• Absorption of synthetic thyroid hormone
• Increasing the dose of medication in hypothyroid patients needed [10]
• Genistein and daidzein from soy (Glycine max)
• Inhibit thyroperoxidase [18]

Sulfadimethoxine (Albon)

Sulfadimethoxine

Sunitinib

• Novel tyrosine kinase inhibitor
• Antitumor and antiangiogenic effects
• Higher than expected rate of hypothyroidism in sunitinib-treated patients
• Of 40 patients
• 21 (53%, 24% of the original 89) developed elevated thyrotropin (TSH) after a median of 5 months (range 1-36 months)
• Median TSH was 21.4 mU/L (range 4.6-174 mU/L) [22]
• In vitro, sunitinib had antiperoxidase activity
• Cca one-fourth the potency of propylthiouracil [22]

T3 binding to nuclear receptors inhibováno / blokováno

Thermally oxidized dietary fats

• Study on rat model
• Raised plasma thyroxine concentration
• Oxidized fats can also alter the morphology and function of thyroid gland [10]

Thiocyanates

• Interfere with iodine uptake [10]

Thiouracil

Thiourea

Thyroid peroxidase - TPO - activity inhibována

• Reduced by
• Saturated FA
• Polyunsaturated n-6 FA [10]

Tobacco smoke

• Also a source of thiocyanate [20]

TPO deficiency

• Geneticky mutace v enzymu
• X glycosylace
• Any mutation affecting a potential glycosylation site (N-X-S/T)
• May alter TPO activity
• Mutations affecting the membrane spanning region disturb
• Insertion of the enzyme into the plasma membrane
• Alter the normal cellular distribution
• Trafficking of the enzyme

TPO-speci?c T cells

• Markers of thyroid in?ltration
• Implicated in thyroid destruction [15]

Triclosan

• May have direct action on thyroid hormone receptor [10]

TSH sekrece inhibována

Tyreostatika

• Most commonly used antithyroid drugs
• Propylthiouracil
• Methimazole
• May block the thyroid hormone synthesis by
• Inhibiting the thyroid peroxidase (TPO)
• Diverting oxidized iodides away from thyroglobulin [21]

Methimazole (MMI)

• Replacement of sulfur with selenium in MMI
• Leads to an interesting compound
• May reversibly block the thyroid hormone synthesis [21]

Propylthiouracil (PTU)

• PTU inhibits the selenocysteine-containing enzyme ID-1
• By reacting with the selenenyl iodide intermediate (E-SeI) [21]

Age

• More common in perimenopausal and menopausal women
• Altered balance between oestrogen and progesterone [10]
• Daily administration of genisteinaglycone (a known goitrogen) to post-menopausal women
• Over a period of 3 years
• Did not modify T3, T4, TSH levels and enzyme activity [10]

Vitamin B12 deficiency

• Implicated in autoimmune thyroiditis [10]

Voda ze studní

• High levels of
• Nitrate
• Humic substances
• Some of their degradation products are goitrogenic
• By blocking thyroidal iodination