Protein degradation in preimplantation mouse embryos and the lethality of tritiated amino acids
The role of protein degradation in preimplantation development in the mouse was studied. Proteins of morulae and blastocysts (M and B) cultured in vitro after labeling for 1 hour (h) in /sup 3/H-leucine exhibit a mean half-life (t/sub 1///sub 2/) of 8.1 h. The t/sub 1///sub 2/ tends to increase (9.5 h) when 10% fetal calf serum is added to the chase medium. This decrease in protein degradation in the presence of serum is associated with an increase in the percentage of B that are hatching (P<0.02). This rate of protein degradation in vivo was affected by the stage of pseudopregnancy (PSP) of the recipient. Day 4 embryos in a Day 4 uterus (Day 1=vaginal plug) retained more of the /sup 3/H-leucine in their proteins than did Day 4 embryos remaining in culture (P<0.02), while Day 4 embryos in a Day 3 uterus retained the same amount of radioactivity as did Day 4 embryos in culture. This differential effect of uterine environment was also seen when Day 4 embryos were transferred to recipients. More fetuses developed to term when the recipient was in Day 3 of PSP (50.8%) than when the recipient was in Day 4 PSP (25.9%, P<0.001), regardless of the age of the recipient. Age of the recipient does affect the percentage of transferred embryos developing to term. Thus, protein degradation may vary with the stage of embryo development and the conditions to which the embryos are exposed. However, even low levels of incorporated tritiated leucine can have lethal effects on the embryos and compromise the validity of the protein half-lives determined.
- Research Organization:
- California Univ., Davis (USA)
- OSTI ID:
- 6627990
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
PROTEINS
BIOLOGICAL HALF-LIFE
DECOMPOSITION
TRITIUM COMPOUNDS
LETHAL DOSES
EMBRYOS
FETUSES
IN VITRO
IN VIVO
LEUCINE
MICE
MORTALITY
ONTOGENESIS
UTERUS
AMINO ACIDS
ANIMALS
BODY
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DOSES
FEMALE GENITALS
LABELLED COMPOUNDS
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
560162 - Radionuclide Effects
Kinetics
& Toxicology- Animals
Plants
Microorganisms
& Cells