The utilization of exogenous taurine for the conjugation of xenobiotic acids in the ferret

Abstract

1. Although the occurrence of the taurine conjugation mechanism for various xenobiotic acids is well established, nothing is known of the source of the taurine used for this conjugation.

2. [¹⁴C]Taurine was administered alone and in combination with 2-naphthylacetic acid or clofibric acid (both of which are known to form taurine conjugates) to ferrets, and the 0-24 h urine collected.

3. Of the dose of [¹⁴C]taurine, 26% was recovered in the urine in 24 h and the only ¹⁴C-containing material present was unchanged taurine.

4. When either 2-naphthylacetic acid or clofibric acid was co-administered with [¹⁴C]taurine, 21 and 17%, respectively, of the ¹⁴C dose was recovered in the 0-24 h urine. In both cases, two ¹⁴C compounds were present—unchanged taurine (minor) and the taurine conjugate of the acid in question (major).

5. Comparison of these results with those previously obtained with ¹⁴C-labelled 2-naphthylacetic and clofibric acids, shows that the taurine used for their conjugation is derived from a pool freely accessible to exogenous taurine.

6. The results are discussed in terms of the availability for metabolic utilization of taurine in the animal body, and of the use of co-administration of [¹⁴C]taurine with a xenobiotic acid for the identification of taurine conjugates.