Use of 75Se-labelled selenite ion for metabolic studies in various animal species

This work was carried out by autoradiography (mice, pigs) and liquid scintillation (rats, rabbits, pigs, ewes). The results obtained show that after intramuscular administration sodium selenite is rapidly absorbed. It is distributed in the different organs, preferentially in the liver, kidney, bone-marrow and heart, where it remains fixed for a long time. In the blood it decreases only slowly. Much of the selenium is excreted, partly during the first 48 hours in urine (20-30%, depending on species), mainly in the seleniate form, and partly in the faecal matter, the latter type of excretion being spread over a longer time (5-8 days). Transfer to milk in the ewes is only slight. From these results it can be stated with certainty that the selenium that is not excreted during the first few hours in the urine or faeces is translocated to the cell structure, particularly the proteic structures. Its chemical relationship to sulphur easily explains this metabolic peculiarity. (author)