Author
Ralston, Nicholas | |
Hunt, Curtiss |
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only Publication Acceptance Date: 12/10/1999 Publication Date: 3/15/2000 Citation: Ralston, N.V.C., Hunt, C.D. 2000. Boron incorporation by RAW 264.7 macrophages as indicated by differences in intracellular and extracellular boron concentrations [abstract]. The Federation of American Societies for Experimental Biology Journal. 14:A539. Interpretive Summary: Technical Abstract: Physiologic amounts of dietary boron affect many aspects of human and animal metabolism. To narrow the search for biomolecules that interact directly with boron, cultured cells and their media were assessed for their relative boron concentrations. RAW 264.7 monocyte-macrophages grown in Dulbecco's MEM +10% fetal calf serum in suspension culture produced 4 to 12 x 10**9 cells that were centrifuged at 450 x g to yield cell pellets of 2 to 6 grams. Cell pellets and triplicate samples of matched quantities of media processed in four independent experiments were digested in teflon digestion vessels. Elemental analysis of digested samples was performed by inductively coupled argon plasma emission spectrophotometry. Cellular boron was present at 0.32 +/- 0.09 nmole/10**9 cells, in comparison to copper at 2.22 +/- 1.00, manganese at 1.30 +/- 0.38, molybdenum at 0.05 +/- 0.01, and zinc at 29.74 +/- 0.84 nmole/10**9 cells. The boron concentration in the cells, 2.32 +/- 0.75 uM, was significantly (p <0.03 in a one tailed t test.) higher than media boron concentrations, 1.35 +/- 0.34 uM. The ratio of boron concentrations in the cells relative to the media was 1.78, similar to the 4.66 ratio observed for copper. The cell:media ratios for manganese and zinc were 85.55 and 26.87 respectively. Boron sequestration by macrophages might be a cell specific phenomenon. For example, our studies of promyleocytic HL60 cells found similar intracellular and extracellular boron concentrations. Our findings indicate that boron uptake and incorporation by RAW 264.7 monocyte-macrophages might be the result of boroester formation with specific biomolecules expressed within or on the surface of these cells. |