Morphological and biochemical effects of excessive amounts of biotin on embryonic development in mice.

Pregnant mice received excessive amounts of biotin either subcutaneously (sc) or orally during gestation. There were no differences in the successful pregnancy rates and number of dead or resorbed fetuses between the control and biotin-treated groups. In biotin-treated groups no increased incidence of fetuses with external malformations was clearly demonstrable. However, biotin accumulated in maternal and embryonic organs; especially, the serum biotin level in the biotin-treated dam was 200-fold higher than that in the control dam. There was a difference in biotinidase activity in maternal serum and placenta between the control and biotin-treated groups. It was concluded that excessive amounts of biotin affected the specific activity of biotinidase in pregnant mice, but did not disturb normal reproductive functions and embryonic development.