[Serotonin effect on the fetus and the feto-maternal relationship in the rat].

1. Treatment with serotonin of pregnant rats does not lead to congenital malformations of the fetus. The substance, however, owns a remarkable lethal effect. With increasing differentiation during day 8-11 of pregnancy, the rate of resorptions grows, beginning with umbilication, death of the fetus occurs generally. 2. 6, 12 and 24 h after application of serotonin on the 15th or 18th day of pregnancy, the placenta is examined. The results support the presumption that death of the fetus after treatment with serotonin refers to a contraction of the umbilical cord. The resulting hyperemia in the placenta can be followed up macroscopically as well as histologically, likewise the rapid beginning of cell death. 3. The very quick proceeding of the necrotic process in brain and liver of the fetus, 15 or 18 days old, is described 6, 12 and 24 h after s.c. serotonin injection. An essentially slower proceeding of destruction is characteristical for cyclophosphamide. 4. Simultaneous treatment of pregnant rats with serotonin and procarbazine or iproniazide, respectively, in small doses intensifies the effect of serotonin. But, vice versa, an intensification of the teratogenical effect of small doses of hydrazine cannot be seen.