I had a question posed to me that I'm not knowledgeable enough to answer so I thought I would pose it here and hope for a little help with my answer. I did a search but haven't really been able to come across the answer I'm looking for. Here is the ?:

"With usage of cytomel, there is downregualtion of the receptors and T3 negative feedback. Does this pertain to the TSH levels plummeting, meaning that the receptors become less responsive due to the adding more than exogenously produced T3, and also there is some mecahnism that goes back through a feedback loop and shuts off the T3 production? Essentially, once the body recognizes the addition of the T3 (by taking cytomel) there are certain functions (downregulation and neg. feedback) that work together in an attempt to keep the normal amount of T3 being produced? How would you overcome the downregulation and neg. feedback if you were running a cycle of T3? I've always had an idea of what downregulation and negative feedback meant, but I wasn't 100 percent positive of how it works in relation all of this."

Thanks for any help.