Urinary Taurine Excretion Research Articles

Sources of excess taurine excreted in rats following whole body irradiation.

Summary1. X-irradiation does not alter concentration of taurine in muscle, spleen, thymus or liver tissue of rats exposed to x-radiation 24 hrs. prior to study. However, during this period, there is a marked increase in urinary excretion of taurine. Thus preformed tissue taurine does not appear to be the source of excess taurine excreted following irradiation. 2. Rats maintained on a diet designed to cause a depletion of sulfhydryl compounds (cholic acid feeding) have a significantly reduced urinary taurine response to whole-body irradiation. 3. When rats maintained on sulfhydryl-depleting diet were given subsequently an l-cystine supplemented diet, the lowered urinary taurine response to irradiation was not restored to normal.

Increased Urinary Excretion of Taurine and Urea by Rats after X-Irradiation

An excessive urinary excretion of taurine and urea has been observed in the rat after whole-body X-irradiation (1-3). Since taurine is one of the major end products of sulfhydryl oxidation (4-7) its excessive excretion suggests an increase in the rate of oxidation of this radical. Barron et al. (8-11) have shown sulfhydryl-containing enzymes to be especially sensitive to inactivation by X-irradiation. In addition, when given prior to irradiation, cysteine (12), glutathione (13), and cysteamine (14, 15) protect against radiation death through a mechanism not due to the redox potential of these substances (16). All these observations indicate a fundamental importance of sulfhydryl groups in radiation damage. Therefore, it appeared that a study of the excretion of the end products of sulfhydryl oxidation would be of value. In addition, since sulfhydryl groups are components of most proteins, the simultaneous investigation of the excretion of the end products of protein degradation might provide additional useful information. Excretion of the sulfur products of metabolism is confined almost entirely to the urine. Therefore, the extent of sulfhydryl oxidation can be estimated by measuring urinary taurine and sulfate, and the extent of protein degradation evaluated by determining urinary urea. This paper will present and attempt to interpret data on the urinary excretion of these compounds by the X-irradiated rat.