Use of EDTA to produce zinc deficiency in the pregnant rat.

The effectiveness of EDTA in reducing the endogenous zinc supply in pregnant rats was determined by two experiments. In experiment 1, a high level of zinc (100 ppm) was given to rats days 15 through 17 of gestation. In experiment 2, a low level of zinc (3 ppm) was given from days 1 through 17. On day 18, half the rats were given EDTA in two intraperitoneal injections 6 hours apart with or without zinc supplementation. The -Zn + EDTA group lost weight continuously after the injections, had increased hematocrit levels prior to parturition,and showed greater stress at parturition than did the -Zn group. Weight gains, hematocrit level, and parturition in the +Zn + EDTA group did not differ significantly from those of the +Zn controls. Spleen weights were decreased in the -Zn + EDTA and -Zn groups and zinc concentration in the spleen increased in the -Zn + EDTA group. Iron concentration decreased in the spleen and increased in the liver of EDTA-treated rats. Use of EDTA to remove endogenous zinc appears to offer a mechanism for study of the effects of short-term zinc supplementation at critical periods in the pregnant zinc-deficient rat.