These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


PUBMED FOR HANDHELDS

Search MEDLINE/PubMed


  • Title: Blastocyst implantation in ovariectomized, adrenalectomized hamsters treated with inhibitors of steroidogenesis during the pre-implantation period.
    Author: Evans CA, Kennedy TG.
    Journal: Steroids; 1980 Jul; 36(1):41-52. PubMed ID: 6447931.
    Abstract:
    The possible involvement of blastocyst estrogen production in the initiation of implantation, as indicated by the presence of areas of increased endometrial vascular permeability on Day 5 of pregnancy, was examined in hamsters. The animals were ovariectomized and adrenalectomized on Day 3 to remove maternal sources of estrogen, and pregnancy was maintained with medroxyprogesterone acetate. Aminoglutethimide phosphate (AGP) and cyano-ketone, inhibitors of steroidogenesis, administered from Days 3 to 5 of pregnancy, did not affect the proportion of hamsters in which implantation was initiated. However, the AGP treatment was associated with a lower proportion of embryos, recovered on Day 4, which were blastocysts, fewer implantation sites on Day 5, and smaller implantation swellings on Day 9. AGP treatment had no significant effect on the uterine concentrations of prostaglandins (PGs) of the E series, which were higher in the implantation sites than elsewhere in the uterus on Day 5. These results suggest that neither maternal nor blastocyst estrogen production is essential for the initiation of implantation in the hamster. In addition, the data suggest that the localized elevated PGE concentrations at implantation sites are induced by a blastocyst signal which is independent of blastocyst steroidogenesis. The possible involvement of blastocyst estrogen production in the initiation of implantation, as indicated by the presence of areas of increased endometrial vascular permeability on day 5 of pregnancy, was examined in hamsters. The animals were ovariectomized and adrenalectomized on day 3 to remove maternal sources of estrogen, and pregnancy was maintained with medroxyprogesterone acetate. (AGP) Aminoglutethimide phosphate and cyano-ketone, inhibitors of steroidogenesis, administered from day 3-5 of pregnancy, did not affect the proportion of hamsters in which implantation was initiated. However, the AGP treatment was associated with a lower proportion of embryos, recovered on day 4, which was blastocysts; fewer implantation sites on day 5; and smaller implantation swellings on day 9. AGP treatment had no significant effect on the uterine concentrations of (PG) prostaglandins of the E series, which were higher in the implantation sites than elsewhere in the uterus on day 5. These results suggest that neither maternal nor blastocyst estrogen production is essential for the initiation of implantation in the hamster. In addition, the data suggest that the localized elevated PGE concentrations at implantation sites are induced by a blastocyst signal which is independent of blastocyst steroidogenesis.
    [Abstract] [Full Text] [Related] [New Search]