My feet & ankles are swollen, hot and reddish color. I have high blood pressure, lupus, asthma, back problems, diabetic, fibromyalgia, and Padgett disease, an enlarged heart, and enlarged thymus gland.
1 Free T4 (Free Thyroxine) â considered a precursor hormone, T4 is converted to T3 as required by cells throughout the body; levels of T4 are generally much higher than T3.  Total T4 (Total Thyroxine) - Most T4 in the blood is bound to carrier proteins which make it biologically inactive. Total T4 includes unbound (free) T4 plus T4 that is bound to carrier proteins in the blood.
Calcium and phospholipase C second messenger mechanisms. Ca+ and phospholipase C second messenger mechanisms by which hormones act on target cells. Hormone binds to receptor on plasma membrane and activates G protein. G protein activates Ca+ channel so Ca+ can enter cell, and activate calmodulin. G protein also activates phosphlipase C, which causes phosphotidylinositol to be broken down into inositol triphosphate (IP3) and DAG.