Biosynthesis of taurine by rat pineals in vitro

Pineal glands from adult, male rats were incubated in oxygenated Krebs-Ringer buffer containing 14C-cystine. After three hours the incubation media and pineal gland extracts were placed separately on Dowex AG W50-X-4 columns. In the elution volume where 14C-labeled taurine is found a labeled peak was recovered. However, when subjected to one or two dimensional paper chromatography especially the eluants from pineal gland extracts yielded two 14C-labeled substances one located in the region where unlabeled taurine is detected by ortho-phthalaldehyde reagent. These results were confirmed utilizing a method developed in our laboratory based on high performance liquid chromatography (HPLC). The pineals, as well as their respective incubation medium, were shown to contain radioactive taurine. These results demonstrate that rat pineal glands are capable of taurine synthesis. Also a high degree of labeling was associated with an area on paper chromatograms, migrating more rapidly than the standards, using acidic solvent systems. If represented by a single pineal compound, the substance must be rapidly synthesized from 14C-cystine to account for the radioactivity observed. Future studies of sulfur metabolism within the pineal gland could be of significant interest.