MODELING DRUG RESIDUE UPTAKE BY EGGS - EVIDENCE OF A CONSISTENT DAILYPATTERN OF CONTAMINANT TRANSFER INTO DEVELOPING PREOVULATORY YOLKS

A study was conducted to determine if the chicken ovary deposits the p esticide lindane into preovulatory egg yolks in a daily pattern simila r to that previously reported for both of the antibiotics ampicillin a nd oxytetracycline. Our laboratory has proposed that a variety of drug s or contaminants are deposited into preovulatory yolks in a consisten t manner. This possibility of a consistent pattern of drug deposition in preovulatory yolks has been used as a foundation for a model which predicts the pattern of residues contained in laid eggs. In two separa te experiments, 16 hens were dosed with 3 mg of lindane per kg of body weight orally approximately 1 h after oviposition (8 hens per experim ent). Twenty-four hours following dosing, hens were sacrificed and the ovaries were collected. Yolks were dissected free from the individual follicles with a blunt probe. Individual large (greater than or equal to 0.2 g) yellow yolks and a pool of 5 small (<0.2 g) yellow yolks we re collected for determination of lindane content. Samples were prepar ed and assayed by using a gas chromatography method. Results indicate the pattern of incorporation of lindane residues in developing yolks i s similar to the previous pattern obtained for both ampicillin and oxy tetracycline. These data confirm the possibility that diverse chemical compounds may be incorporated into preovulatory yolks in a similar pa ttern, supporting a key component of our model, which predicts the pat tern of incurred residues in laid eggs for a variety of drugs or conta minants.