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Discussion Starter · #1 ·
Hello guys, I have a question and I hope you can help me.
We know that thyroxine T3 & T4 can cross the cell membrane and bind to intracellular receptors while catecholammines can't so they bind to extracellular receptors. My question is why?
I mean I know that thyroxine is lipophilic while catecholamines are hydrophilic, but why is that? they are both tyrosine derivatives and they both contain polar groups.
I really appreciate any help you can provide.
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