Discrimination between the effects of X-ray irradiation of the mouse oocyte and uterus on the induction of dominant lethals and congenital anomalies.

In order to test whether irradiation of the postimplantation maternal environment had any effect on the apparent induction of dominant lethals or congenital anomalies by radiation, preimplantation embryos were surgically transferred between females which had been irradiated before conception or left untreated. A high proportion of preimplantation embryos, collected from females that had been irradiated 15-21 days prior to conception with 3.6 Gy X-rays, were either arrested or developmentally retarded compared with those collected from untreated females. The transfer experiments indicate that irradiation of the uterus has no significant effect on the frequency of subsequent postimplantation mortality or on mean fetal weight. However, it remains unclear whether irradiation of the uterus contributes to the induction of congenital anomalies.

Discrimination between the effects of X-ray irradiation of the mouse oocyte and uterus on the induction of dominant lethals and congenital anomalies. II. Localised irradiation experiments.

In order to evaluate whether irradiation of the postimplantation maternal environment contributed to the induction of postimplantation mortality or congenital anomalies, mouse ovaries were surgically exteriorised and selectively irradiated or shielded in a specially constructed apparatus. The results show that exposure of the mouse abdomen and uterus to 3.70 Gy X-rays, 15-21 days prior to conception, has no significant effect on the incidence of either postimplantation mortality or congenital anomalies. Exposure of the ovaries to 3.27 Gy X-rays during the same period, however, increased the frequency of both postimplantation mortality and congenital anomalies.