Serum iron in other molecules in cells throughout the body. None of this iron is directly accessible by testing the serum. However, some iron is circulating in the serum. Transferrin is a molecule produced by the liver that binds one or two iron(III) ions, i.e. ferric iron, Fe; transferrin is essential if stored iron is to be moved and used. Most of the time, about 30% of the available sites on the transferrin molecule are filled. The test for serum iron uses blood drawn from veins to measure the iron molecules that are bound to transferrin, and circulating in the blood. The
P-glycoprotein verapamil can be used for measuring P-gp function with positron emission tomography. P-gp is also used to differentiate transitional B cells from naive B cells. Dyes such as rhodamine 123 and MitoTracker dyes from Invitrogen can be used to make this differentiation. P-glycoprotein P-glycoprotein 1 (permeability glycoprotein, abbreviated as P-gp or Pgp) also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) or cluster of differentiation 243 (CD243) is an important protein of the cell membrane that pumps many foreign substances out of cells. More formally, it is an ATP-dependent efflux pump with broad