Sources and turnover rates of taurine in nursing and weaned rat pups.

The quantitative importance of the molar as a source of taurine for neonatal rats has been examined by maintaining female rats on a diet containing 3H-taurine until they were uniformly labeled, and then mating them. Rats were kept on the 3H-taurine diet throughout pregnancy and lactation. The transfer of taurine from the mother to the pup both in utero and during nursing could thus be followed, and the quantity of taurine biosynthesized by the pup calculated. Pups were weaned at 21 days of age onto either a taurine-free diet or a diet containing 0.4% of non-radioactive taurine. The loss of 3H-taurine from various organs was followed. Whole body half-life of 3H-taurine was 11.4 days from rats fed the taurine-enriched diet and 15.0 days for rats on the taurine-free diet. Regardless of the diet, internal organs and the brain had faster rates of turnover that turnover from the muscle or from the whole animal. Both groups showed the same increase in total body taurine in the 4 weeks after weaning, indicating that young rats can biosynthesize considerable quantities of taurine.