Local secretory response by the mouse uterine epithelium to the presence of a blastocyst or a blastocyst-like bead

Abstract

The ultrastructure of the uterine secretion appearing locally at the site of a blastocyst or a blastocyst-like bead was compared to the ultrastructure of the secretion present in a sterile horn of similarly treated mice. The secretion consisted of a homogeneous substance with small vesicles. The secretion was sparse and only slightly electron dense in a sterile horn, while it was more abundant and denser in a horn with a luminal object. Around a blastocyst, the secretion appeared more dense than it did around a bead, while the small vesicles of the secretion were more frequently occurring around a bead than around a blastocyst. It is concluded that a luminal object like a blastocyst is capable of eliciting a local secretory activity in the uterine epithelium, and it is suggested that this secretion is rich in hydrolytic enzymes.

Lectins, Calcium Ionophore A23187 and Peanut Oil as Deciduogenic Agents in the Uterus of Pseudopregnant Mice: Effects of Tranylcypromine, Indomethacin, Iproniazid and Propanolol

“…In addition, Enders and Schlafke (1974) found that Con A was capable of binding to surface glycoproteins of mouse uterine epithelial cells and showed that the binding properties of the lectin were abolished by il-methyl-D-mannoside. The present results are in conflict to some extent with those of Nilsson (1977). He found that Con A-Sepharose beads in the uterus of hormonetreated ovariectomized mice altered the ultrastructure of the uterine epithelium and elicited a local secretory activity, but did not cause any decidual reaction.…”

Differences in Amino Acid Content of Preimplantation Mouse Embryos that Develop in Vitro Versus in Vivo: In Vitro Effects of Five Amino Acids that are Abundant in Oviductal Secretions1

“…Modulation of transport by the uterus not only might influence the levels of these amino acids in embryos but also could influence their concentrations in the uterine environment near blastocysts. Very little uterine fluid appears to surround blastocysts near the time of implantation [36]. Hence it is conceivable that increases and decreases in the activities of transport systems B°' + and XAG-could greatly alter the concentrations of glutamine, glutamate, and aspartate in uterine secretions surrounding periimplantation blastocysts.…”

Conversion of pregnenolone to progesterone by mouse morulae and blastocysts

“…elevated lactic acid level (Gupta et ai, 1970), decreased thymidine incorporation (Freese et ai, 1973), and modified embryo transport through the oviduct (Betteridge et ai, 1976;Villalon et ai, 1982)] and the uterus [e.g. increased capillary permeability (Psychoyos, 1973;Dickmann et ai, 1977), increased uterine secretion (Nilsson, 1977;Aitken, 1977), and changes in oestrogen receptors (Martel & Psychoyos, 1981;Puri & Roy, 1981)]. It is also possible that the embryo's steroidogenic ability could be a mechanism to improve its chance of survival when the maternal source of steroid hormones is deficient for the optimal stimulation of the reproductive tract.…”