Kinetic behavior of thallium in the rat. Accelerated elimination of thallium owing to treatment with potent diuretic agents.

1. In acute experiments anesthetized rats were treated with a subthreshold dose of 204Tl+, given intravenously in order to study the elimination kinetics of Tl+. Thallium disappeared from whole blood by means of two different half-lives (5 and 196 min, respectively), whereas VDbeta amounted to 1400 ml. The same kinetic parameters were found after chronic exposure to toxic amounts of Tl+. 2. After chronic exposure to thallium (10 or 30 ppm in the drinking water), the distribution of thallium over various organs proved non-specific. However, a pronounced accumulation was found in the renal medulla. 3. In view of the importance of the renal route in the elimination of Tl+ from the body and also because of the established accumulation of the toxic metal in the kidney, the influence of potent diuretic agents like furosemide and ethacrynic acid on the excretion of Tl+ was studied. The enhanced excretion of water and ions (Na+, K+, Cl-) was accompanied by a significantly accelerated excretion of thallium ions. High doses of ethacrynic acid (25 mg/kg) proved particularly powerful in this respect. Between the enhanced excretion of thallium and potassium ions a significant correlation was obvious, thus supporting the well-known similarity in the behaviour of these ions. The marked increase in renal elimination of thallium upon intensive diuretic treatment may be useful in the management of thallotoxicosis.