Sulfate concentrations in cerebrospinal fluid and serum of rabbits and cats

Abstract

The mean ratio between the sulfate concentrations in the cerebrospinal fluid (CSF) and the serum of rabbits was 0.17 and of cats 0.24. In cats 1 and 7 days of age the CSF/serum ratios were 0.30 and 0.35. After the intravenous administration of Na2SO4 to rabbits, the SO4 content of the CSF increased during the first 8 hr. In the ensuing 16 hr this concentration was maintained. In normal and in SO4-injected preparations successive CSF samples increased markedly in sulfate content. This may be due to the formation of a transudate by the choroidal plexuses because of the abnormal pressure relations in the brain case. Alternately a transudate of the pial vessel which normally is swept away by fluid formed by the choroidal plexuses may be collected under the experimental conditions. If the SO4 content in in the CSF is used for the computation of the sulfate (extracellular) space instead of the serum concentration, values of 15-30% of the tissue volume result.