High-performance size-exclusion chromatography of 63Ni-constituents in renal cytosol and microsomes from 63NiCl2-treated rats.

Fractionations of 63Ni-constituents were performed by high-performance size-exclusion chromatography upon samples of renal cytosol and washed renal microsomes from rats that were killed 1 h after an im injection of 63NiCl2 (50 or 125 mumol/kg body wt). The kidney homogenates contained 2.0 +/- 0.4% of the total dose of 63Ni. Renal cytosol contained 55 +/- 5% and washed microsomes contained 5.4 +/- 1.2% of 63Ni that was present in the kidney homogenates. Chromatography of renal cytosol on TSK-GEL SW-2000 and SW-3000 separated 63Ni into six fractions. The largest component (Fraction F) contained approximately 80% of cytosolic 63Ni. Since Fraction F was eluted near the total permeation volume of SW-2000 columns and beyond the total permeation volume of SW-3000 columns, its molecular weight could not be reliably estimated. The other components, which comprised collectively the remaining 20% of cytosolic 63Ni, had apparent molecular weights of 168,000 (Fraction A), 84,000 (Fraction B), 51,000 (Fraction C), 24,000 (Fraction D), and approximately 10,000 (Fraction E). Solubilized washed microsomes from kidneys of 63NiCl2-treated rats contained 63Ni in five components with elution profiles and 63Ni-contents that resembled Fractions A, B, D, E, and F of renal cytosol, based upon chromatography on SW-3000 columns. The solubilized microsomes also contained a 63Ni-component with high molecular weight (Fraction M, greater than 700,000 daltons), which accounted for 3% of microsomal 63Ni. This study provides a rapid, convenient, and reproducible technique to fractionate 63Ni-components in tissue extracts, and it demonstrates in vivo binding of 63Ni to several constituents of renal cytosol and microsomes from 63NiCl2-treated rats.