Female reproductive properties and prenatal development of a senescence-accelerated mouse strain.
Female reproductive properties, early embryonic development, and serum estradiol and progesterone levels of the senescence-accelerated mouse (SAM)-prone (SAM-P) strain were compared with those of a SAM-resistant (SAM-R) strain. The reproductive life span of SAM-P (from 11.4 to 25.0 weeks old) was shorter than that of SAM-R (11.1 to 41.6 weeks old), and the total number of SAM-P pups was 41.7% less than from SAM-R. The reproductive senescence of SAM-P is more accelerated than that of SAM-R. At 15 weeks old, the maximum litter size of SAM-P was noted and was 33.7% smaller than that of SAM-R. Although no differences in the numbers of ovulated and fertilized ova were observed between two strains, the number of implants in SAM-P was 21.6% less than in SAM-R. Cell cleavage was delayed in embryos of SAM-P (8% morula, at day 2 of pregnancy) compared to SAM-R (48%). At day 3 of pregnancy, 9% and 33% of the embryos were blastocysts in SAM-P and SAM-R, respectively. At day 1 of pregnancy, serum estradiol level in SAM-P was 18.2% higher than in SAM-R, whereas the serum progesterone level in SAM-P was 46.2% lower than in SAM-R. The unbalance of estradiol and progesterone levels in SAM-P was considered to be the cause of the delay in early embryonic development, and then the decrease of implantation and a smaller litter size.
Miyamoto
H
H
Department of Animal Science, Kyoto University, Japan.
Manabe
N
N
Mitani
Y
Y
Sugimoto
N
N
Watanabe
T
T
Aruga
C
C
Sato
E
E
D000375:Aging / Q000502:physiology*; D000818:Animals; D010064:Embryo Implantation / Q000502:physiology; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000502:physiology; D005260:Female; D051379:Mice; D008815:Mice, Inbred Strains / Q000502:physiology*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D012098:Reproduction / Q000502:physiology*
D011374:Progesterone; D004958:Estradiol