Fluoride Tissue Distribution: Intracellular Fluoride Concentrations 1

Abstract

Abstract

The distribution of fluoride and chloride in muscle, liver, and tendon was studied in groups of 6-15 rats sacrificed at 80-240 min after intraperitoneal injections containing radiofluoride (¹⁸F) and radiochloride (³⁶Cl). Liver exhibited a constant ¹⁸F(tissue water):¹⁸F(plasma water) ratio over 120-220 min and this ratio was constant in muscle over 80-120 min. The ¹⁸F_tw/¹⁸F_pw ratios for muscle were lower than those of liver. The ratios of ¹⁸F distribution for both liver and muscle declined significantly at the longest time periods probably as a result of reductions of intracellular pH and/or increases of extracellular pH. Chloride space volumes were determined from chloride analyses of the tissues and plasma and confirmed by the ³⁶Cl(tissue water):³⁶Cl(plasma water) ratios. The fluid space volumes and the ¹⁸F(tissue water):¹⁸F(plasma water) ratios were used to indicate that the average intracellular ionic fluoride concentrations of liver and muscle are, respectively, 79 and 38% that of plasma water. The relative intracellular fluoride concentrations of liver and muscle are related to their respective values of intracellular pH. The entire water of tendon was found to be available to chloride, analytically determined, and to ³⁶Cl and ¹⁸F.