Summary
The ultrastructure of the endometrial epithelium of the pig was studied during the estrous cycle and early pregnancy up to implantation. Special attention was given to the luminal epithelium and morphological indications of protein synthesis.
Although the general morphology of the luminal and glandular epithelia is similar (both tissues consist of secretory cells and ciliated cells at all the stages studied), it appears that the two epithelia should be considered as two functionally different units in the pre-implantation period.
Morphological evidence suggests the presence of at least three different secretory products within luminal epithelial cells; they are released at different times, i.e. at estrus, between day 8 and 10 and after day 11. The glandular epithelium shows release of secretory products from day 10–11.
Increasing amounts of glycogen were found within epithelial cells, especially in pregnant gilts from day 12.
The possible significance of secretory activity of the epithelium is discussed in relation to the development of the embryos.
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References
Barends PMG, Taverne N, Stroband HWJ, Blommers PCJ (1985) Embryonic development of the pig: Ultrastructure and uptake of macromolecules during early pregnancy. Cell Biol Int Rep 9:517
Bazer FW, Roberts RM (1983) Biochemical aspects of conceptusendometrial interactions. J Exp Zool 228:373–383
Bazer FW, Thatcher WW (1977) Theory of maternal recognition of pregnancy in swine based on estrogen controlled endocrine versus exocrine secretion of prostaglandin F2α by the uterine endometrium. Prostaglandins 14:397–400
Cheng S (1981) Auswirkungen der Superovulation von Jungsauen auf Wachstum, Morphologie und Proteinsekretion des Uterus und auf die Embryonalentwicklung in der Präimplantationsphase. University of Göttingen: Thesis
Corner GW (1921) Cyclic changes in the ovaries and uterus of the sow and their relation to the mechanism of implantation. Contrib Embryol 13:119–146
Dantzer V (1984) An extensive lysosomal system in the maternal epithelium of the porcine placenta. Placenta 5:117–130
Dantzer V (1985) Electron microscopy of the initial stages of placentation in the pig. Anat Embryol 172:281–293
Duenbostel K von, Paufler S (1983) Rasterelectronenmikroskopische Untersuchungen der Oberflächenstruktur des weiblichen Genitaltrakts vom Schwein im Stadium des Diöstrus. DTW 90:528–533
Fazleabas AT, Hansen PJ, Geisert RD, Robers RM (1984) Differential patterns of uteroferrin and plasmin inhibitor induction and their immunocytochemical localization within the pig uterus. Biol Reprod [Suppl 1] 30:41
Fazleabas AT, Bazer FW, Hansen PJ, Geisert RD, Roberts RM (1985) Differential patterns of secretory protein localization within the pig uterine endometrium. Endocrinology 116:240–245
Fischer HE, Bazer FW, Fields MJ (1985) Steroid metabolism by endometrial and conceptus tissues during early pregnancy and pseudopregnancy in gilts. J Reprod Fertil 75:69–78
Geisert RD, Renegar RH, Thatcher WW, Roberts RM, Bazer FW (1982a) Establishment of pregnancy in the pig: I. Interrelationships between preimplantation development of the pig blastocyst and uterine endometrial secretions. Biol Reprod 27:925–939
Geisert RD, Brookbank JW, Roberts RM, Bazer FW (1982b) Establishment of pregnancy in the pig: II. Cellular remodelling of the porcine blastocyst during elongation on day 12 of pregnancy. Biol Reprod 27:941–955
Geisert RD, Thatcher WW, Roberts RM, Bazer FW (1982c) Establishment of pregnancy in the pig: III. Endometrial secretory response to estradiolvalerate administered on day 11 of the estrous cycle. Biol Reprod 27:957–965
Heap RB, Flint APF, Gadsby JE, Rice C (1979) Hormones, the early embryo and the uterine environment. J Reprod Fertil 55:267–275
Helmond F, Aarnink A, Oudenaarden C (1986) Periovulatory hormone profiles in relation to embryonic development and mortality in pigs. In: Steenan JM, Diskin MG (eds): Embryonic mortality in farm animals. Martinus Nijhoff publishers, Dordrecht Boston Lancaster, pp 119–125
Krzonkalla C (1979) Das Epithel der Uterusschleimhaut des Schweines während der Implantation. University of Munich, Thesis
McRae A (1984) The blood-uterine lumen barrier and its possible significance in early embryo development. Oxford Rev Reprod Biol 6:129–173
Miller BG, Moore NW (1983) Endometrial protein secretion during early pregnancy in entire and ovariectomized ewes. J Reprod Fertil 68:137–144
Murray FA, Bazer FW, Wallace HD, Warnick AC (1972) Quantitative and qualitative variation in the secretion of protein by the porcine uterus during the estrous cycle. Biol Reprod 7:314–320
Murray FA, Moffatt RJ, Grifo AP (1980) Secretion of riboflavin by the porcine uterus. J Anim Sci 50:926–929
Perry JS, Crombie PR (1982) Ultrastructure of the uterine glands of the pig. J Anat 134:339–350
Perry JS, Rowlands IW (1962) Early pregnancy in the pig. J Reprod Fertil 4:175–188
Pope WF, First NL (1985) Factors affecting the survival of pig embryos. Theriogenology 23:91–105
Raub TJ, Bazer FW, Roberts RM (1985) Localization of the iron transport glycoprotein, uteroferrin, in the porcine endometrium and placenta by using immunocolloidal gold. Anat Embryol 171:253–258
Roberts GP, Parker JM (1974) Macromolecular components of the luminal fluid from the bovine uterus. J Reprod Fertil 40:291–303
Sinowatz F, Friess AE (1983) Uterine glands of the pig during pregnancy. An ultrastructural and cytochemical study. Anat Embryol 166:121–134
Stroband HWJ, Taverne N, Bogaard M vd (1984) The pig blastocyst: its ultrastructure and the uptake of protein macromolecules. Cell Tissue Res 235:347–356
Wu ASH, Carlson SD, First NL (1976) Scanning electron microscopic study of the porcine oviduct and uterus. J Anim Sci 42:804–809
Zavy MT, Roberts RM, Bazer FW (1984) Acid phosphatase and leucine aminopeptidase activity in the uterine flushings of nonpregnant and pregnant gilts. J Reprod Fertil 72:503–507
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This work was carried out within the framework of the “Working-Party on Early Pregnancy” of the Agricultural University
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Stroband, H.W.J., Taverne, N., Langenfeld, K. et al. The ultrastructure of the uterine epithelium of the pig during the estrous cycle and early pregnancy. Cell Tissue Res. 246, 81–89 (1986). https://doi.org/10.1007/BF00219003
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DOI: https://doi.org/10.1007/BF00219003