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|Title:||The Use of Delayed Implantation Model in The Study of Hormonal Requirement for Implantation in The Rat|
|Author(s):||Nasution, Syahrun Hamdani|
|Department / Program:||Animal Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Biology, Animal Physiology|
|Abstract:||A delayed implantation rat model has been developed. Method of ovariectomy was described. Ovariectomy could be performed up to the morning of day 4, beyond that ovariectomy was not effective. Injection of Tamoxifen (10 or 50 (mu)g/200 g BW) in the afternoon of either day 4 or day 5 inhibited implantation. Subcutaneous injection of 1.0 microgram of estrone induced implantation in 100% of the delayed implantation rats used, while lower (0.1 (mu)g/200 g BW) and higher doses (5.0 (mu)g/200 g BW) resulted in fewer implantation. Similarly, diethylstilbestrol induced implantation when given at doses of 0.5 and 1.0 (mu)g/200 g BW. The more effective dose, 0.5 (mu)g/200 g BW resulted in only 50% of rats implanted.
A blastocyst transfer method was used to study the hormonal effect of implantation. Blastocysts were introduced into the uterine lumen by a fine polyethylene tubing. The recipient uteri was sensitized by the injection of 1.0 (mu)g of estrone 4-6 hours before transfer. Delayed implanting blastocyst had the same capacity to implant as blastocysts from day 5 gestation. Therefore, delayed implantation blastocysts were used in the transfer experiment, because in this model, the time of the induction of implantation is precisely known. Delayed implantation blastocysts had also been shown to be viable for a long as 8 weeks in the state of delay.
Using the blastocyst transfer method, it was found that 10 pg of estradiol 17-beta (E2) per ml induced in 56% of the blastocysts. This dose resulted in a significantly higher number of implantation sites compared to the lower E2 doses tested (1.0 pg/ml and 0.1 pg/ml). The actual amount of E2 transferred was only 0.016 pg/rat. Ten microgram of PGF2-alpha per ml instilled the same way as E2 resulted in 50% of the blastocysts implanted. Higher dose of PGF2-alpha, however, caused false positive readings. Indomethacyn in doses of 0.2 (mu)g/ml or larger, completely blocked the E2 induction effect of implantation. Based on these results and on other reported studies, it was concluded that the initiation of implantation by estrogen may involve the synthesis of prostaglandin by the endometrium which is adjacent to the blastocysts.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
|Date Available in IDEALS:||2014-12-15|