Turnover of Taurine in Rat Tissues

Abstract

The equilibrium of taurine between the various tissues of the rat was measured in order to determine those tissues with a unique role in taurine metabolism. The rate of uptake and the change in specific activity (SA) of ³⁵S-taurine in each of the major tissues was followed from 1 hour through 14 days after an intraperitoneal injection of a tracer dose of ³⁵S-taurine. The SA generally corresponded to the uptake or ³⁵S level. The majority of the ³⁵S was found in the carcass (43% of dose after 1 hour; 60% after 14 days) and the skin-hair (14% of dose after 1 hour; 6% after 14 days). Only 18% of the injected ³⁵S was recovered in the urine during 14 days. Tissues with a rapid turnover of taurine (t_0.5 < 1 day) were liver, kidney, adrenal and pancreas. Testes, spleen, lung, intestine and intestinal contents had a moderate rate of taurine turnover (1 < t_0.5 < 3 days). Heart, skeletal muscle and brain had a slow turnover of taurine (t_0.5 > 3 days). Taurine was not metabolized to a significant extent in any of these tissues. The data indicate that taurine is actively absorbed by all tissues of the rat. Taurine turnover rates reported for each tissue suggest important metabolic roles for taurine in addition to conjugation of bile salts.