A method for studies on milk excretion of chemicals in mice with 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) as a...

A simple and rapid milking technique for mice is described by which multiple milk samples can be collected from anaesthetised dams after 1h separation from the litter. Three samples of milk were collected from each dam by aspiration via a flexible tubing fitted to the nipple and approximately 0.3-0.5 ml milk was obtained at each time point. The milking technique was tested with 14C-labelled 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) as a model substance. A rapid and efficient milk excretion of BDE-99, with a milk/plasma ratio of approximately 40, was demonstrated. During the studied 7 days most of the given dose was excreted in milk with peak levels already 4-10 h after an intravenous administration. Higher tissue concentrations of BDE-99 were found in suckling neonates than in dams, probably due to a high dose per kilogram body weight from milk and an efficient absorption via the gastrointestinal tract in the pups.