The present investigation has been undertaken to understand the mechanism of mammalian implantation process, by demonstrating the role of ovarian steroids in the differentitation of the reproductive organs.

Attempt was made to examine the activity of alkaline phosphatase(ALP) in the oviduct, antimesometrium and the mesometrium of the uterine on Day 3 and Day 6.

1) The difference of the activity in the oviduct was not founded on Day 3 and Day 6.

2) The effect of estradiol on the differentiation of the oviduct was appeared on Day 3.

3) The difference of differentiation was not founded in the animesometrium and the mesometrium on Day 3.

4) The activity of ALP in the antimesometrium was higher than that in the mesometrium on Day 6.

5) The activity of ALP in antimesometrium on Day 6 was significantly higher than that observed on Day 3.

6) The effect of ovarian steroid homones on the differentiation of the uterine endometrium on Day 6 was obviously higher than that on Day 3. In particular, the effect of progesterone was markdly observed on Day 6.

This study, therefore, clearly demonstractes that estradiol is effective the differentiation of the oviduct preparing implantiation, but progesterone has much potent in the antimesometrium differentiation at the immplantation period.

This study has been done in order to verify the localization of alkaline phosphatase(ALP) activity, in connection with the mechanism of seceretion and absorption of luminal fluid in the mouse uterus during estrous cycle. The localization of ALP has been carried out by using a modified Ernst(1972)¹²⁾ method. The results of these experiments were as followings: The reaction product by ALP activity was localized in general at the luminal and glandular epithelia, and the wall of blood vessels of endometrium. At diestrus stage, luminal surface and basal lamina of the epithelia showed a moderate reaction products by ALP activity. However, the intensity of ALP activity was not even according to the region. As the cyclic stage transited from proesturs to estrus the reaction product at the basal lamina region and on the luminal surface, which showed a lot of well developed microvilli, appeared gradually heavier to be come maximum at estrus stage. It is implying that the most active transport of luminal fluid occurs at these region during estrus stage. At metaestus stage, the reactive product at the same sites as estrus stage appeared light with some symptomes of degeneration. Some of secretory cells on the luminal epithelium had mitochondria with dense granules in their matrix. Therefore, from the above result it is strongly suggested that the chages in the localization and intensity of ALP activity on the luminal and glandular epithelia, and blood vessels might be closely correlated with the secretion and absorption of the luminal fluid in the uterus during estrous cycle.

The purpose of the present study is to measure concentration of plasma estradiol and progesterone and to determine the concentration of the estradiol receptor in the uterine endometrium at the early pregnant rat.

The results obtained were as followings:

1) Plasma estradiol concentration showed the highest value on day 1 and the lowest on day 2, increasing again on day 3 and 4.

2) Concentration of plasma progesterone increased sharply on day 3, maintaining gradual increase thereafter. Rats ovariectomized on day 2, however maintained lower progesterone levels than those of day 1, throughout the preimplantational period.

3) The concentration of nuclear estradiol receptor seemed to be well correlated with the concentration of plasma estradiol throughout the preimplantation peried. Treatment of estradiol appeared to increase the concentration of estradiol receptor on day 3 and 6 in ovariectamized rats.

4) The differentiation of the uterine endometrial tissue seemed to be closely related to ovarian steroid hormones.

The present investigation has been undertaken to understand the mechanism of implantation process, by demonstrating the role of ovarian steroids in the differentiation of uterine endometrium for implantation. We observed that the phosphatase activities seem to be dependent upon the ovarian steroids ; that is the activity showed higher level in progesterone treated group than in estradiol treated one, and the highest activity was found in the group treated with both estradiol and progesterone. The differentiation of the uterine endometrial tissue seemed to be closely related to ovarian steroid hormones ; estradiol seemed to effect on the differentiation of the luminal and glandular cell and progesterone on the formation of collagen fiber of the stromal cells, thereby inducing decidualization. Ovarian steroids might stimulate phosphatase synthesis thereby inducing differentiation of luminal and glandular tissues and then development of the uterine stromal cell for triggering decidualization in pregnant rats.

Quantitative analysis of the activities of phosphatase in ovariectomized rat uterus was carried out.

1. The activities of total phosphatase were decreased by ovarian steroids (except progesterone treated group at pH 9).

2. The ratio of acid: alkali, neutral phosphatase was 4 : 1.

3. Among total enzymes, the proportion of Mg⁺⁺ - dependent phosphatase was much higher than the other specific enzyme.

4. The activities of alkali, acid phosphatase were decreased by cystein, but the activity of neutral phosphatase was increased.

5. At the neutral media, the experimental group treated with progesterone and estradiol-17β on day 1 appeared the following special figures.

(1) The activity of total phosphatase was low.

(2) K⁺ - dependent phosphatase was negligible.

(3) Mg⁺⁺ - dependent phosphatase transformed into Mg⁺⁺ - independent phosphatase.

(4) The activity of phosphatase was stimulated by cystein.

6. These results means the fact that phosphatase activity is affected by ovarian steroids, and by pH.

In vivo treatment of theophylline, we have obtained results and summarized them as below. 1) Effects of theophylline on ovulation, and maturation of the oocytes in mouse; (1) The group treated with theophylline at the time of PMS injection, showed marked decrease of the ovulation rate. (2) If theophylline was given to the animals at the time of injection of HCG, the maturality of the oocytes in the Graafian follicles seemed to be inhibited. 2)Effects of the theophylline on the maturality of the oocytes ovulated, and fertilizability of the eggs. (1) The female mice injected with theophylline with PMS remarkably desreased in mating rate. (2) If treatment of theophylline was made with HCG injection, oocyte maturation was inhibited. (3) The production of 2-cell embryo markedly decreased in either group treated with theophylline with PMS or with HCG. 3) Theophylline effect on implantation of the embryos. (1) Pregnancy rate was markedly decreased in both group of control and theophylline treatment.

Citations

Citations to this article as recorded by  

• Cyclic nucleotide phosphodiesterase inhibitors: possible therapeutic drugs for female fertility regulation
  Anumegha Gupta, Ashutosh N. Pandey, Alka Sharma, Meenakshi Tiwari, Pramod K. Yadav, Anil K. Yadav, Ajai K. Pandey, Tulsidas G. Shrivastav, Shail K. Chaube
  European Journal of Pharmacology.2020; 883: 173293.     CrossRef