1996 Volume 11 Issue 1 Pages 30-37
We investigated the feto-placental transfer and excretion into the milk after single intravenous administration of 125I-YM866 to pregnant rats or nursing rats.
1. After administration of 125I-YM866 to pregnant rats on day 14 of gestation, a little radioactivity was transferred to the fetus, and most of the distributed radioactivity was not precipitable with trichloroacetic acid (TCA). Therefore, the radioactivity in the fetus was confirmed to be low molecular weight metabolites and/or free 125I.
2. After administration of 125I-YM866 to pregnant rats on day 19 of gestation, transfer of radioactivity to the fetus was minimal as revealed by the whole-body autoradiograms.
3. After administration of 125I-YM866 to nursing rats on day 14 after delivery, comparatively high radioactivity was transferred to the milk. But in the lactating rats, the plasma and tissue concentrations of radioactivity were less than 1/8 of that in the clotted milk in the stomach, suggesting that the absorption of radioactivity from the intestinal tract was low.
