tokens: To test whether Cd exposure would increase Ca release from bone during pregnancy and lactation in relation to the etiological mechanism of Itai - Itai disease , virgin female mice with 45Ca prelabeled skeletons ( 15 microCi / mouse ) were subjected to one round of pregnancy / lactation and were exposed to a Ca - deficient diet containing 0 , 5 , or 25 ppm Cd or 25 ppm Pb for 32 days , from conception until Lactation Day 14 .