Search

Molecular interactions and cellular exchanges between mother and foetus or embryo in pregnancy generate an intimate symbiosis of two different lives. Interpersonal communication is an established requirement in the life of each man to reach personal plenitude. Initially on a biological basis, each person is open to others and his surroundings. While the body of the child is developing in the womb of the mother, the mother prepares the "last finish", which will allow him to assimilate and adapt to his peculiar world. In parallel, the brain of the mother, stimulated by hormones and pregnancy factors, becomes ready for a rich and complex behaviour.

Recent studies, have shown that pre-implanted embryos of several species synthesize steroid hormones: progesterone, progestins , androgens and several estrogens and it has been postulated that oviductal and endometrial functions are influenced by blastocyst synthesis and release of these molecules. Steroids may create an appropriate milieu for blastocyst migration, nutrition, development and implantation in the maternal uterus. It is the purpose of this paper to review a possible physiological role of steroid hormonal synthesis by the early embryo during the first stages of pregnancy.

Among the studies realized in preimplanted embryos, draw attention to its endocrine capacity to synthesize steroid hormones: progesterone, progestins and several estrogens, which may influence locally the properties of the oviduct and endometrium creating and appropriate environment for its nutrition, migration and further development in order to let its implantation in the maternal uterus. Among the steroids secreted by the conceptus, estrogens are of special interest because of their potential importance in the biochemical events associated with the process of implantation. The purpose of this review is to contribute to the knowledge of the biosynthesis and metabolism of estrogens realized by the early embryo.

In order that blastocyst implantation occurs in mammals, it is required the synthesis and secretion of several substances including steroid hormones by the preimplanted embryo. In this paper, we analyze the embryo endocrine capacity for biosynthesis and secretion of progesterone and several progestines.

In order that blastocyst implantation occurs in mammals, it is required the synthesis and secretion of several substances including steroid hormones by the preimplanted embryo. In this paper, we analyze the embryo endocrine capacity for biosynthesis and secretion of progesterone and several progestines.

The fixed position of trophoblast in the uterus is preceded by zygote orientation and its contact, adhession and fusion with endometrial cell membrane. These interactions take place in a precise site called "implantation site". The identification of this area by the administration of pontamine blue has allowed biochemical studies which showed an increase (in the site) of glycolytic enzymes activity of the pentose cycle, of beta-glucuramidase and of acid and alkaline phosphatase; with a decrease in catepsine D activity. In non implanted tissue, isocitric dehydrogenase activity is decreased. From the biochemical standpoint the implanted endometrium may be different from the rest, which allows a better knowledge of possible molecular mechanisms related with implantation, as well as the possible inhibition with medication.