Metal ion transport quantified by ICP-MS in intact cells

Abstract

The use of ICP-MS to measure metal ion content in biological tissues offers a highly sensitive means to study metal-dependent physiological processes. Here we describe the application of ICP-MS to measure membrane transport of Rb and K ions by the Na,K-ATPase in mouse skeletal muscles and human red blood cells. The ICP-MS method provides greater precision and statistical power than possible with conventional tracer flux methods. The method is widely applicable to studies of other metal ion transporters and metal-dependent processes in a range of cell types and conditions.

Figure 1. The S content of mouse skeletal muscles is an accurate index of tissue mass.

(a) total S content of each sample vs. weighed mass. Different symbols represent different muscles and conditions. , EDL muscles incubated for 10 min in physiological saline containing 4.7 mM RbCl in place of KCl; , EDL muscles incubated for 10 min in the same solution +1 mM ouabain; EDL muscles incubated in 200 μM RbCl and 4.7 mM KCl; EDL muscles incubated in the same solution +1 mM ouabain; ο, untreated EDL muscle removed from the animal without incubation; , untreated TA muscles. Slope = 3.82 × 10³ , correlation coefficient = 0.9868 (b) Muscle mass computed from the S content of each sample (S-based mass) vs. weighed mass. Slope = 0.786, correlation coefficient = 0.987.

Figure 2. Rb taken up by RBCs in the absence and presence of 1 mM ouabain, measured by ICP-MS and referred to Fe based mass.

The RSD for each group was 1.6%.