Elimination profile of methylthiouracil in cows after oral administration

in addition to methods for the determination of residues, there is an impor tant need for knowledge of the fate and excretion of growth promoting subst ances in fattening animals. In court, often simple questions are asked, suc h as, over what period of time can the drug be detected?, is it possible to find residues after 2 months, etc. These questions can only be answered by conducting animal experiments. Data on excretion and distribution of thiou racils in cows are rather scarce. At the beginning of the 1980s, animal exp eriments with methylthiouracil (MTU) were carried out in the Laboratory of Chemical Analysis. These experiments showed that treatment of cows with MTU results in the rapid appearance of the drug in plasma, urine and milk, whe reas MTU selectively accumulates in the thyroid gland. The results of these experiments were only published in media with limited access (thesis, abst racts) and also there has been a considerable improvement in data handling with computer programs in the last 15 years. This investigation reinterpret s the 'old' analytical data from animal experiments using a pharmacokinetic software package.