ACCUMULATION OF RADIOACTIVITY IN RAT-BRAIN AND PERIPHERAL-TISSUES INCLUDING SALIVARY-GLAND AFTER INTRAVENOUS ADMINISTRATION OF C-14 D-ASPARTIC ACID

After the intravenous administration of C-14-D-aspartic acid (Asp) int o Spraque-Dawley rats (male, 7-week-old), the distribution and elimina tion of radioactivity was investigated by the whole body autoradiograp hy. High radioactivities were detected in pineal gland, pituitary glan d and salivary gland at 30 min after administration. The other tissues detected were liver, lung, adrenal gland, pancreas and spleen where D -Asp was reported to occur naturally. After 24 hr, the radioactivities were still detected at high levels in the pineal, pituitary and saliv ary glands. The data suggested the natural occurrence of D-Asp in sali vary gland. After careful examination utilising fluorescent derivatiza tion and chiral separation by high-performance liquid chromatography, the presence of D-Asp was, for the first time, demonstrated in salivar y gland in situ, the concentration of which was 7.85+/-1.0 nmol/g. The administration of C-14-L-Asp was also carried out. The data suggested that D-Asp in the circulating blood is one of the sources of the tiss ue D-Asp.