ABSTRACT The effects of maternal hyperthermia on the prenatal development of the guinea pig lens is described with particular reference to cataract formation. Cataracts were observed at birth most commonly following maternal hyperthermia in early pregnancy (Ell-25) but also at mid-pregnancy (E39-46) and in late pregnancy (E56-60). Cell death was observed in the lens and neural retina up to 8 hours following heating at E21 and vacuoles were frequently found in the lens fibres immediately beneath the anterior lens epithelium. After heating at El8 and observation at E26 the vesicles in the anterior part of the lens fibres were of varying sizes with the smaller appearing to coalesce into larger vesicles. These vacuoles may be an example of compromised lens fibres whose cellular changes may remain latent and form cataracts in later life following any event which alters fluid balance of the lens.
ABSTRACT The effects of the AY gene on the normal development were investigated by using a inbred strain of C57BLi6 (ah) and its congenic strain of C57BU6-Ay (A%) mice. Three mating groups (female X male), i.e., group I, ala x ala; group 11, aia X Apia; and group 111, A% X aia, were set, and the rating of normal development was compared among the groups on gestation days 13, 14, 15 or 16 with special attention to the secon- dary palate. On day 13, the palates were wide-open and the palatal shelves were vertical in all embryos in all groups. In group I, both shelves became horizontal in 63.3% of the embryos on day 14. The incidences of embryos having completely closed palates were 95.8% and 100% on days 15 and 16, respectively. In group 11, in which half of the embryos were expected to carry the AY gene, the frequencies of shelf horizontalization on day 14 (31.1%) and of the complete closure on day 15 (74.3%) were significantly lowered as compared with those in group I, although the external morphological rating was compa- rable. On day 16, however, the palatal closure was completed in almost all embryos. In group 111, in which maternal mice as well as half of their embryos carried the AY gene, the external morphological rating was delayed as compared with that in either group I or 11, and the frequencies of shelf horizontalization on day 14 and of the complete closure on day 15 were as low as 10.9% and 39.6%, respectively. The palatal closure was not yet completed in 15.3% of the embryos on day 16. These results indicate that the AY gene causes a delay in shelf horizontalization and closure of the secondary palate of mouse embryos as compared with the a gene.
ABSTRACT Male mice of inbred strain C57BL/6 were intraperitoneally treated with ethylnitrosourea (ENU). On days 64-80 after the treatment, the males were mated with untreated virgin females of the same strain and allowed to utilize sperm that were sperma- togonial stem cells at the time of treatment. On day 18 of gestation, viable fetuses were inspected for external malformations. The frequency of externally malformed fetuses in the ENU-treated series increased significantly over the control level. Malformations oc- curred spontaneously in the control series were microphthalmia and micrognathia. In the ENU-treated series as well, they occurred and no other malformations were encountered. The frequencies among total malformations of microphthalmia were 95% and 92% in the control and the ENU-treated series, respectively. Based on these results and other data, we propose that the male-mediated teratogenesis represents spontaneous teratogenesis that is enhanced over the normal level by paternally transmitted germ-line mutation(s).
ABSTRACT The sexually dimorphic nucleus of the preoptic area (SDN-POA) and the anteroventral periventricular nucleus of the preoptic area (AVPvN-POA) are sexually di- morphic regions in the rat brain. These regions are sensitive to reproductive function-re- lated drugs, and thus applied for aromatase inhibitor evaluation in the present study. Effects of NKSOl (an aromatase inhibitor) and tamoxifen on the SDN-POA and AVPvN- POA were examined. Five mg of NKSOl or its vehicle was injected to SD male and female rats from days 1 to 14 (the day of birth = day 0). Other 10 males and 10 females received a single injection of 100 pg tamoxifen on day 1. Rats in each group were sacri- ficed at day 30 or 60. The SDN-POA was examined at days 30 and 60, and the AVPvN- POA at day 60. When NKSOl was given to male rats for the first 14 days of life, a significant reduction of SDN-POA size was observed on day 60. When tamoxifen was given, SDN-POA reduction in size was also observed at days 30 and 60 in male rats. As for the AVPvN-POA, tamoxifen markedly reduced volume in female rats, resulting in polycystic ovaries at day 60. This may be due to an estrogenic property of tamoxifen. On the other hand, NKSOl was not significantly effective in the AVPvN-POA, although the volume of the nucleus in NKSOl males was inclined to increase. From these results, as well as the SDN-POA, the AVPvN-POA may be useful to evaluate the side effect of reproductive function-related drug.