抄録
Development and enzyme activities of embryos during the preimplantation period were examined to reveal causes of the age-related embryonic loss in the golden hamster. Embryos were obtained from young (9-12-week old, n=40) and aged hamsters (43-53-week old, n=40) on Days 2, 2.5, 3 and 3.5 of pregnancy and the number and developmental stages were recorded. In order to compare the viability of the embryos, the metabolic activities of mitochondria, microsomes, plasma membrane and lysosomes were examined histochemically. Early embryos from aged hamsters showed delays in their development and transport through the oviduct compared to those from young females. The embryos exhibiting strong activities of succinate dehydrogenase, isocitrate dehydrogenase and Δ5-3β-hydroxysteroid dehydrogenase were significantly diminished in the aged females. The present results suggest that the reduced metabolic activity may be one possible reason for the retarded development of embryos and that the asynchronous development and delayed migration of the embryos into the uterus may partly account for the embryo loss in the aged hamsters.
