Osmotic effects of sorbitol accumulation in monkey kidney epithelial cell cultures

It has been observed that primary monolayer cell cultures derived from monkey kidney cortex behave in a similar manner to the mammalian lens in that they accumulate high concentrations of sorbitol when they are incubated in medium containing a high glucose concentration (33 mM). An investigation was undertaken to determine whether the accumulation of sorbitol by these cultures results in cellular damage by an osmotic mechanism similar to that which has been proposed to occur in the lens. Phase-contrast microscopy and histochemical investigations revealed that no changes in the cell size, cell growth rate, or cell staining properties occurred as a result of exposure of the cell cultures to a glucose concentration of 33mM for up to 4 days. The cell protein and myo-inositol concentrations and fatty acid composition were also unaffected, as was the incorporation of radioactivity from [U-14C]leucine into cell protein. The rate of 86Rb influx of the cell cultures was decreased and the rate of 86Rb efflux was increased by incubation in medium containing a glucose concentration of 33 mM. Frome these observations it was concluded that the accumulation of sorbitol by monkey kidney epithelial cell cultures did not exert a pathabolic influence upon their growth and metabolism, and that these cells, unlike the lens, have the capacity to compensate adequately for changes in transmembrane osmotic gradients induced by sorbitol accumulation.