Tissue slices prepared from renal cortex of littermate dogs with chronic metabolic acidosis or alkalosis were incubated in media with or without arsenite and containing 1 mM L-[14C]glutamine or [1,5-14C]citrate. The presence of arsenite increased the concentration of alpha-ketoglutarate in slices by 5--20 times the values found without this inhibitor. alpha-Ketoglutarate concentrations in acidotic slices were 40% or more greater than those in alkalotic ones when arsenited was present. 14C incorporation into alpha-ketoglutarate was also increased manyfold by arsenite with either labeled glutamine or citrate as substrate. 14CO2 production from labeled glutamine by over 90% and from labeled citrate by over 75%; the difference between 14CO2 production by acidotic and alkalotic slices was greatly reduced or eliminated by arsenite. These results suggest that in chronic metabolic acidosis metabolism of both glutamine and citrate is stimulated at a site or sites preceding formation of alpha-ketoglutarate.