Reproduction and Lactation in Rats Fed Excessive Iodine

Abstract

In a series of experiments adult female rats were fed zero to 2500 ppm supplemental iodine from zero to approximately 35 days prepartum. Females were permitted to litter normally and the survival of the young was observed. Other females were killed either between 17 and 19 days of pregnancy or between 24 and 48 hours postpartum to observe ovulation rate, implantation rate, development of normal fetuses and histology of mammary tissue. Increasing mortality of young after birth occurred with increasing levels of iodine. Most young failed to survive for 24 hours and those that survived 48 to 72 hours postpartum usually survived until weaning. Those failing to survive had essentially no milk present in the stomach. Visual observation and histological examination of mammary tissue from females fed iodine revealed that secretion was absent or markedly diminished.