Trisomies and triploidies in hamster embryos: induction by low-pressure hypoxia and pH imbalances.

The authors produced trisomic and triploid embryos by mating hamster females approximately 1 hr before estimated ovulation and subsequently submitting them to low-pressure atmospheres equivalent to those found at mountain altitudes for 6 hr. During hypoxic exposures in the low-pressure chamber, the continuous monitoring of pH levels--both subcutaneously and intramuscularly--registered pH decreases from inital values as high as 7.6 to below 6.9. These findings indicate that trisomies in some embryos and triploidies in others have their origin in different, but related mechanisms involving maternal pH imbalances between ovulation and fertilization.