Combination of levo and lio results in rats

[mstp]

I came across this paper just now that discussed thyroid treatments in depth and was interested to see the differing effects of combining levo and lio compared with levo-only treatment in rats.

"Thyroidectomized rats given 1.0 μg levothyroxine/100 g bodyweight have high serum TSH levels, normal T3 levels in the cerebral cortex, and low levels in the heart and the liver. If the levothyroxine dose is increased to 1.6 μg/100 g bodyweight, the serum TSH level is normal, the T3 level in the cerebral cortex is high, low in the heart and normal in the liver. Only a combination of levothyroxine 0.9 μg/100 g bodyweight and liothyronine 0.15 μg/100 g bodyweight results in normal serum TSH and normal T3 concentrations in cerebral cortex, heart, and liver."

I know this isnt a human study but it did make me wonder whether I should stop my liothyronine-only treatment and re-introduce levothyroxine. The full paper can be read on:

onlinelibrary.wiley.com/doi...

[greygoose]

Why did it make you wonder that?

[Zephyrbear]

I might be able to see a point to what you’re asking if the rats were given T3 only and come up with those results, but they weren’t. They were given T4 mono therapy and things only improved once the T3 was added… It’s the addition of T3 that “normalised” their readings.

[Brightness14]

Poor Rats