Low zinc concentration in rat uterine fluid after 4 days of dietary deficiency.

Pregnant rats were fed a purified diet either complete (100 ppm zinc) or zinc-deficient (0.4 ppm zinc) from the day of mating (day 0). On day 4 of pregnancy, the zinc concentration of uterine fluid in rats fed the deficient diet was only half that of controls, although protein concentration was the same. It is proposed that the low concentration of uterine fluid zinc is responsible for the abnormal development of preimplantation embryos reported earlier under these conditions.