Dawson K M, Collins J L, Baltz J M
Loeb Medical Research Institute, University of Ottawa, Ontario, Canada.
Biol Reprod. 1998 Aug;59(2):225-32. doi: 10.1095/biolreprod59.2.225.
Mouse zygotes and early cleavage-stage embryos are sensitive to increased osmolarity. However, development can occur at higher osmolarities if any of a number of organic compounds are present. One of the most effective of these is glycine. We have found that the amount of glycine accumulated by embryos during in vitro culture from the zygote to two-cell stage depends on the osmolarity of the medium, with significantly more glycine accumulated at 310 or 340 mOsM than at 250 mOsM. The accumulated glycine is largely retained in a freely diffusible form, as it can be released via a swelling-activated pathway in two-cell embryos. Increased glycine accumulation does not seem to depend on an increase in its rate of transport. The transport rate is not higher in two-cell embryos that have been cultured from zygotes in hypertonic vs. normal medium, and hypertonicity only slightly stimulates transport in zygotes. Our results indicate that glycine functions as an organic osmolyte in early mouse embryos.
小鼠受精卵和早期卵裂期胚胎对渗透压升高敏感。然而，如果存在多种有机化合物中的任何一种，在较高渗透压下也能发育。其中最有效的一种是甘氨酸。我们发现，胚胎在体外从受精卵培养到二细胞阶段期间积累的甘氨酸量取决于培养基的渗透压，在310或340毫渗摩尔浓度下积累的甘氨酸明显多于250毫渗摩尔浓度时。积累的甘氨酸大部分以可自由扩散的形式保留，因为它可以通过二细胞胚胎中的肿胀激活途径释放。甘氨酸积累的增加似乎并不取决于其转运速率的提高。从受精卵在高渗培养基与正常培养基中培养而来的二细胞胚胎的转运速率并不更高，高渗仅轻微刺激受精卵中的转运。我们的结果表明，甘氨酸在早期小鼠胚胎中作为一种有机渗透剂发挥作用。
