Prostaglandin secretion by perifused porcine endometrium: Further evidence for an endocrine versus exocrine secretion of prostaglandins
Department of Dairy Science, University of Florida, Gainesville 32611. Prostaglandins
04/1988; 35(3):327-41. DOI: 10.1016/0090-6980(88)90126-8
Bilateral perifusion devices were utilized for measurement of prostaglandin secretion by luminal and myometrial surfaces of porcine endometrium. Tissues were collected from Days 10, 12 and 14 pregnant, Day 14 cyclic and Day 14 estrogen-induced pseudopregnant gilts. Each tissue was placed into duplicate perifusion devices and perifused with Krebs-Ringer Bicarbonate solution at 3 ml/10 min for 2 h, fractions collected every 10 min and oxytocin (1 IU/ml) perifused during fractions 6-10 to the luminal side of one chamber and to the myometrial side of the other chamber. Secretion rates of PGF were higher (P less than 0.05) than PGE2 for each status. Secretion rates of PGF and PGE2 were higher (P less than 0.01) from the luminal side for Day 12 pregnant, Day 14 pregnant and Day 14 pseudo-pregnant gilts, whereas secretion was higher from the myometrial side for Day 10 pregnant and Day 14 cyclic gilts. Oxytocin increased (P less than 0.01) prostaglandin secretion from the luminal side regardless of reproductive status. Pregnancy at Day 12 and Day 14, as well as estrogen treatment, were associated with prostaglandin secretion in a luminal (exocrine) orientation versus a myometrial (endocrine) orientation for Day 14 cyclic and Day 10 pregnant gilts. These data indicate an estrogen associated switch between Days 10 and 12 of pregnancy from an endocrine to an exocrine secretion of prostaglandins.
Available from: Robert C Burghardt
- "The concept of a servomechanism in pigs is based on evidence that E2 induces PRLR in uterine LE and GE for shifting secretion of PGF from an endocrine to an exocrine direction for pregnancy recognition . As well, there are synergies between P4, E2 and PRL from the maternal anterior pituitary gland that allow for greater secretory activity of uterine GE in pigs [57-60]. "
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ABSTRACT: There is a dialogue between the developing conceptus (embryo-fetus and associated placental membranes) and maternal uterus which must be established during the peri-implantation period for pregnancy recognition signaling, implantation, regulation of gene expression by uterine epithelial and stromal cells, placentation and exchange of nutrients and gases. The uterus provide a microenvironment in which molecules secreted by uterine epithelia or transported into the uterine lumen represent histotroph required for growth and development of the conceptus and receptivity of the uterus to implantation. Pregnancy recognition signaling mechanisms sustain the functional lifespan of the corpora lutea (CL) which produce progesterone, the hormone of pregnancy essential for uterine functions that support implantation and placentation required for a successful outcome of pregnancy. It is within the peri-implantation period that most embryonic deaths occur due to deficiencies attributed to uterine functions or failure of the conceptus to develop appropriately, signal pregnancy recognition and/or undergo implantation and placentation. With proper placentation, the fetal fluids and fetal membranes each have unique functions to ensure hematotrophic and histotrophic nutrition in support of growth and development of the fetus. The endocrine status of the pregnant female and her nutritional status are critical for successful establishment and maintenance of pregnancy. This review addresses the complexity of key mechanisms that are characteristic of successful reproduction in sheep and pigs and gaps in knowledge that must be the subject of research in order to enhance fertility and reproductive health of livestock species.
Available from: biolreprod.org
- "Other secretions of the uterine epithelia are also sequestered within the uterine lumen to provide histotroph to support conceptus development during pregnancy. We used an Ussing Chamber-type device to demonstrate that endometria from cyclic pigs release PGF toward the myometrium and vasculature (endocrine direction), whereas endometria from pregnant and estrogen-treated gilts release PGF from the luminal side of the endometrium (exocrine secretion). However, the mechanism whereby estrogens, acting either alone or in concert with prolactin, mediate the shift from endocrine to exocrine secretion of PGF is not known. "
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ABSTRACT: I became interested in biology as an undergraduate in a premedical curriculum but developed a passion for the field of reproductive biology because of a course in physiology of reproduction taken to meet requirements for admission to veterinary school. My career path changed, and I entered graduate school, obtained the Ph.D., and have enjoyed an academic career as a reproductive biologist conducting research in uterine biology and pregnancy in animal science departments at the University of Florida and at Texas A&M University. However, I have never allowed academic boundaries to interfere with research and graduate education as that is contrary to collegiality, the cornerstone of great universities. I consider that my major contributions to science include 1) identification of proteins secreted by cells of the uterine endometrium that are critical to successful establishment and maintenance of pregnancy; 2) discovery of steroids and proteins required for pregnancy recognition signaling and their mechanisms of action in pigs and ruminant species; 3) investigation of fetal-placental development and placental transport of nutrients, including water and electrolytes; 4) identification of linkages between nutrition and fetal-placental development; 5) defining aspects of the endocrinology of pregnancy; and 6) contributing to efforts to exploit the therapeutic value of interferon tau, particularly for treatment of autoimmune diseases. My current studies are focused on the role of select nutrients in the uterine lumen, specifically amino acids and glucose, that affect development and survival of the conceptus and translation of mRNAs and, with colleagues at Seoul National University, gene expression by the avian reproductive tract at key periods postovulation. Another goal is to understand stromal-epithelial cell signaling, whereby progesterone and estrogen act via uterine stromal cells that express receptors for sex steroids to stimulate secretion of growth factors (e.g., fibroblast growth factors and hepatocyte growth factor) that, in turn, regulate functions of uterine epithelial cells and conceptus trophectoderm.
Available from: Mark A. Mirando
- "In addition, treatment with oestradiol enhanced the response of luminal epithelial cells to OT and increased PGF 2α secretion from the apical surface . These latter effects are in general agreement with the increased responsiveness to OT of luminal epithelial cells from pregnant pigs (Uzumcu et al. 2000) and are likely to contribute to the increased exocrine secretion of PGF 2α in response to OT that occurs during early pregnancy (Gross et al. 1988; Carnahan et al. 1999). In contrast, oestradiol clearly reduced the PGF 2α secretory response of stromal cells to OT on Day 16 in the present study, an effect that could contribute to reduced endocrine secretion of PGF 2α from cells that are in closest proximity to the uterine vasculature during pregnancy recognition (Carnahan et al. 1996; Edgerton et al. 1996). "
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ABSTRACT: These studies were undertaken to determine how treatment with 100 nM progesterone and/or 10 nM oestradiol-17beta acutely (3 h; Experiment 1) or chronically (72 h; Experiments 2-4) influenced basal and oxytocin (OT)-stimulated prostaglandin (PG) F(2alpha) secretion, in enriched cultures of pig endometrial luminal epithelial, glandular epithelial and stromal cells obtained on Day 16 (Experiments 1, 2 and 4) or Day 12 (Experiment 3) after oestrus. In Experiment 1, acute treatment with progesterone stimulated PGF(2alpha) secretion from each cell type on Day 16, whereas acute oestradiol treatment inhibited the stimulatory action of progesterone on PGF(2alpha) secretion only in glandular epithelial cells. In Experiment 2, OT stimulated phospholipase (PL) C activity in luminal epithelial cells on Day 16 only in the presence of chronic oestradiol treatment. For glandular epithelial cells on Day 16, OT stimulated PLC activity only in the presence of chronic treatment with steroid. In stromal cells on Day 16, OT stimulated PLC activity in the absence of steroids and the response to OT was further enhanced by oestradiol. In the absence of chronic treatment with steroid, OT did not stimulate PGF(2alpha) secretion from luminal epithelial cells, but oestradiol induced a response to OT. For glandular epithelial cells, OT-induced PGF(2alpha) secretion was not altered by steroids, whereas the stimulatory response to OT was inhibited by oestradiol or progesterone in stromal cells. For endometrial cells obtained on Day 12 after oestrus in Experiment 3, OT only stimulated PGF(2alpha) release from glandular epithelial and stromal cells. For luminal epithelial cells obtained on Day 16 after oestrus and cultured under polarizing conditions in Experiment 4, secretion of PGF(2alpha) occurred preferentially from the basolateral surface and was stimulated by OT more from the basolateral surface than from the apical surface. Oxytocin-induced PGF(2alpha) secretion from the apical surface was enhanced by chronic treatment with oestradiol, whereas that from the basolateral surface was enhanced by chronic treatment with progesterone. In summary, oestradiol enhanced OT-induced PGF(2alpha) secretion from the apical surface of luminal epithelial cells and reduced the response of stromal cells to OT, actions that may contribute to the reorientation of PGF(2alpha) from endocrine secretion (i.e. towards the uterine vasculature) to exocrine secretion (i.e. towards the uterine lumen) during pregnancy recognition in pigs.
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