rT3 og TSH

[Vigdis]

Dr Kent Holtorf har skrevet en artikkel om hvordan blodprøver ikke forteller hele sannheten om stoffskiftet http://nahypothyroidism.org/thyroid-...e-whole-story/

Reverse T3 (RT3) levels are also important to examine. Reverse T3 is a marker for reduced T4 to T3 conversion. T4 can either be converted to T3 (energy) or RT3, which is the inactive form of T3 and has antithyroid effects. If too much RT3 is made in proportion to FT3, the excess RT3 blocks the T4 from getting into the cells, effectively blocking the effect of the thyroid.

The best indicator of thyroid hormone levels in the cells is the FT3/RT3 ratio. In healthy individuals, the RT3 is usually below 250 pg/ml, and the Free T3/Reverse T3 ratio is greater than 1.8 (if Free T3 is in ng/dl) or 0.018 (if Free T3 is in pg/ml).

If you feel tired all the time and have the typical symptoms of hypothyroidism, and also have any of the physical issues mentioned, perhaps you should ask your doctor to look deeper into your thyroid health. All it takes is a simple blood test to measure your Free T3/Reverse T3 ratio. Getting the right tests and diagnosis could mean the difference between living a life with energy or suffering with unnecessary fatigue and other health issues.

[Vigdis]

Reverse T3

TSH and serum T4 levels fail to correlate with intracellular thyroid levels. Additionally, the free T3 will also tend to be less accurate with reduced cellular energy. This artificial elevation of T3 due to be reduced uptake into the cell is generally offset by a reduced T4 to T3 conversion due to reduced uptake and T4 and subsequent conversion to T3, making T3 a more accurate marker than the TSH or T4 with physiologic stress. Also, the transporter for reverse T3 (rT3) is similar to T4 in that it is energy dependent and has the same kinetics as the T4 transporter (6,41,45,62,66,67). This property (among others) makes it the most useful indicator of diminished transport of T4 into the cell (45).

Thus, a high reverse T3 demonstrates that there is either an inhibition of reverse T3 uptake into the cell and/or there is increased T4 to reverse T3 formation. These always occur together in a wide range of physiologic conditions and both cause reduced intracellular T4 and T3 levels and cellular hypothyroidism. Thus, reverse T3 is an excellent marker for reduced cellular T4 and T3 levels not detected by TSH or serum T4 and T3 levels. Because increased rT3 is a marker for reduced uptake of T4 and reduced T4 to T3 conversion, any increase (high or high normal) in rT3 is not only an indicator of tissue hypothyroidism but also that T4 only replacement would not be considered optimal in such cases and would be expected to have inadequate or sub-optimal results. A high reverse T3 can be associated with hyperthyroidism as the body tries to reduce cellular thyroid levels, but this can be differentiated by symptoms and by utilizing the free T3/reverse T3 ratio, which is proving to be the best physiologic marker of intracellular thyroid levels (see Diagnosis of low thyroid due to stress & illness Graph). Fra http://nahypothyroidism.org/thyroid-...ort/#reverseT3 Gå til artikkelen om du vi kikke på forskning som nevnes i parentes ved tall, en milelang referanseliste!

Økt rT3 er altså en markør for redusert opptak av T4 og redusert T4 til T3 konvertering.

[Vigdis]

Konklusjon
http://nahypothyroidism.org/thyroid-...rt/#conclusion

Conclusion

The most important determinant of thyroid activity is the intra-cellular level of T3, and the most important determinant of the intracellular T3 level is the activity of the cellular thyroid transporters (1-67). Reduced thyroid transport into the cell is seen with a wide range of common conditions, including insulin resistance, diabetes, depression, bipolar disorder, hyperlipidemia (high cholesterol and triglycerides), chronic fatigue syndrome, fibromyalgia, neurodegenerative diseases (Alzheimer’s, Parkinson’s and multiple sclerosis), migraines, stress, anxiety, chronic dieting and aging (1-43,46,49,51,52,53,58,60,66,68,69,72-118).

This high incidence of reduced cellular thyroid transport seen with these conditions makes standard thyroid tests a poor indicator of cellular thyroid levels in the presence of such conditions. The pituitary has different transporters than every other tissue in the body; the thyroid transporters in the body are very energy dependent and affected by numerous conditions while the pituitary is minimally affected. Because the pituitary remains unaffected, there is no elevation in TSH despite wide-spread tissue hypothyroidism, making the TSH an inaccurate marker for tissue T3 levels under the numerous conditions listed above (1,3,4,17,22,43,50,52,55,59,60,61).

The reduced thyroid transport seen with these conditions results in an artificial elevation in serum thyroid levels (especially T4), making this a poor marker for tissue thyroid levels as well (5,40,41,49,52,53,62,66,67). An elevated or high-normal reverse T3 is shown to currently be the best marker for reduced transport of thyroid hormones and an indication that a person has low cellular thyroid levels despite the fact that standard thyroid tests such as TSH, free T4, and free T3 are normal (6,32,41,45,62,66,67,125-172) (see Diagnosis of low thyroid due to stress & illness Graph).

The intracellular T3 deficiency seen with these conditions often results in a vicious cycle of worsening symptoms that usually goes untreated because standard thyroid tests look normal. Additionally, it is not surprising that T4 preparations are generally ineffective in the presence of such conditions, while T3 replacement is shown to be beneficial, with potentially dramatic results (71,74,75,76,80,81,82,86,97,98,99,100,101,102,103,104,105,17 3-198). In the presence of such conditions, it should be understood that significant intracellular hypothyroidism may exist that remains undiagnosed by standard blood tests (the freeT3/reverse T3 ratio may aid in the diagnosis). Thus, more appropriated testing beyond standard thyroid function tests should be considered and supplementation with T3 should be considered with such patients.

Jeg anbefaler å lese denne artikkelen, og flere andre på dette nettstedet. Artikkelen er lang, men den kan være en øyeåpner.

For dere som bruker ren T4, Levaxin, men ikke blir friske, kan lesningen av http://nahypothyroidism.org/thyroid-...ort/#treatment være en inngang for å få legen til å gi dere T3 i en eller annen form. Mange referanser der som kan tas med, samt gode argumenter for hvorfor akkurat du bør få T3

[Anisa]

For dere som bruker ren T4, Levaxin, men ikke blir friske, kan lesningen av http://nahypothyroidism.org/thyroid-...ort/#treatment være en inngang for å få legen til å gi dere T3 i en eller annen form. Mange referanser der som kan tas med, samt gode argumenter for hvorfor akkurat du bør få T3

Utroligt sammenfald, Vigdis. Jeg har postet i dag "beslægtet" i emnet > Reverse T3 and CT3M.