Embryopathic effects of different routes of administration of mercuric acetate in the hamster

A comparison was made between 4 modes of administration of mercuric acetate into the pregnant golden hamster on Day 8 of gestation, i.e., intraperitoneal (ip), intravenous (iv), oral (o) and subcutaneous (sc) in respect to induced embryonic damage. The embryos were recovered either 4 or 6 days later and the number of resorption sites and abnormal embryos were recorded. The major manifestations of embryonic damage included an increased resorption rate, and small, retarded, and edematous embryos. Several miscellaneous congenital malformations were also detected. In general these embryopathic effects as well as indicators of maternal toxicity were dose dependent for each mode of administration. Primarily on the basis of equivalent resorption rates the following sequence of decreasing efficacy in producing harmful effects was demonstrated; ip > iv > sc > o. The results are discussed within the general context of the known deleterious effects of mercury on biological systems and the controversy regarding the transmission of inorganic mercury from the pregnant animal to the developing embryo.