A33-year-old chemist takes l-thyroxine (synthroid) 1 ug orally each day. he asks how the thyroxine work a cellular level. which of the following is the best explanation?
a) it binds onto membrane surface receptor and activates protein synthesis.
b) it binds onto membrane surface receptor and activates secondary messenger.
c) it binds onto a cytoplasmic receptor and the hormone-receptor complex diffuses to the nucleus to affect transcription.
d) it has a direct effect on the hypothalamic nuclei affecting metabolism