Comparison of the effect of Ascaris trypsin inhibitor in various periods of mouse pregnancy.

Trypsin inhibitor isolated from Ascaris suum and injected into pregnant BALB/c mice (five times, in doses: 300 or 400 mg/kg/day) in various periods of pregnancy (early and late organogenesis) disturbed the development of fetuses. The nature and intensity of prenatal disturbances are determined by the inhibitor dose and time of injection. It has been found that administration of the inhibitor from 5-th until 9-th day of gestation did not delay or prevent implantation, but caused a high rate of intrauterine deaths and also specific congenital malformations (exnencephaly and hydrocephalus). Additionally, other types of defects were noted in fetuses after injection of the inhibitor between 8-th and 12-th day of pregnancy (cleft palate, fusion of ribs). Independent of the time of injection during gestation the inhibitor exhibited embriotoxic effects (e.g. decreased the number of live fetuses per litter and mean fetal weight).