Hormonal Regulation of Porcine Uterine Protein Secretion

Summary. Progesterone and oestrone alone or in combination were administered to sows during early gestation. A dose of 25 mg progesterone and 12\m=.\5 \g=m\g oestrone injected together for 10,5 or 2 consecutive days during the implantation interval caused increased litter size at term.The effect of exogenous steroid hormones on embryonic survival in the pig is unclear. While pro¬ gesterone given alone during gestation has no, or even a detrimental effect on embryo viability (Sammelwitz, Dziuk & Nalbandov, 1956;Haines, Warnick, Wallace & Edwards, 1957;Spies, Zimmerman, Self & Casida, 1959), the administration of progesterone and oestrogen has been re¬ ported to increase embryo survival (Reddy, Mayer & Lasley, 1958;Day, Romack & Lasley, 1963 Progesterone (A*-pregnen-3,20-dione: Sigma Chemical Co.) and oestrone (A1,3,5(10)-estratrien-3-ol-17-one: Sigma Chemical Co.) solutions were prepared as described by Reddy et al. (1958) and injected i.m. in volumes of 2 or 4 ml at invervals of 23-25 hr. The control and hormone treatments used are shown in Table 1. Control animals received cottonseed oil at corresponding times of treat¬ ment administration, but because there were no differences in mean litter size in the various subgroups, these results were pooled into one control group (Group 0).The number ofsows returning to oestrus, the number carrying the litter to term and the total number of pigs farrowed were recorded. Mean litter size was calculated and statistically tested by least squares regression analysis (Harvey, 1960).Conception rate was high in all treated sows and did not differ from that in controls. There was no effect of breed of sow or individual boar on litter size results (least squares regression analysis). As shown in Table 1, there was a significant increase in litter size when progesterone and oestrone were administered from Days 14-23 (Group 2), a period during which implantation is occurring (Green & Winters, 1946). Administration of both steroids for shorter intervals at this time resulted in increased litter size only in Groups 4 and 6. There was no effect of treatment on the number of pigs stillborn.

supporting

confidence: 84%

Effect of administration of progesterone and oestrogen on litter size in pigs

Wildt¹,

Culver²,

Morcom³

et al. 1976

“…In most eutherian mammals the induction of uterine secretory activity (Urzua, Stambaugh, Flickinger & Mastroianni, 1970;Arthur & Daniel, 1972;Knight, Bazer & Wallace, 1973) and the initiation of implantation (Nalbandov, 1971 ;Cumming, Baxter & Lawson, 1974;Murphy & Mead, 1976) are under the control of progesterone. In the mouse (Yoshinaga & Adams, 1966) and rat (Canivenc & Laffargue, 1956;Yoshinaga, 1961;Psychoyos, 1973;Surani, 1975), however, these events require the presence of oestrogen as well as progesterone.…”

Section: Discussionmentioning

confidence: 99%

Changes in the protein content of mouse uterine flushings during normal pregnancy and delayed implantation, and after ovariectomy and oestradiol administration

Aitken¹

1977

Summary. The protein content of the mouse uterine lumen increased significantly (P < 0\m=.\001) on Day 4 of pregnancy, the day of implantation. This increase was associated with the presence of 14 serum and 22 non-serum proteins in the lumen; the major serum proteins were classed as high molecular weight slow \g=a\-globulins, while the dominant non-serum components consisted of slow and fast \g=a\-globulins, 6 prealbumins and a large quantity of proteinaceous material migrating near the origin of the gels.During experimental and lactational delayed implantation the protein levels were constantly low, transferrin, haemoglobin and albumin dominating the protein pattern. After administration of oestradiol-17\g=b\,however, a biphasic uterine response was detected, significant increases in luminal protein concentration being observed within 12 h and again at 40\p=n-\48h after injection. The first phase of this response involved an influx of serum and non-serum proteins into the uterine lumen, most proteins migrating as high molecular weight slow \g=a\-globulins. The second phase involved an increase in the intensity of many non-serum components, the major proteins having Ra values of 0\m=.\06,0\m=.\10and 0\m=.\32.The qualitative, but not the quantitative, aspects of this response to oestradiol were identical in the absence of blastocysts.

“…Histotroph is required to support conceptus development; therefore, the conceptus produces hormones and cytokines to stimulate or silence expression of genes by uterine LE/sGE and GE as necessary for pregnancy recognition signaling for maintenance of a functional CL to produce P 4 required for establishment and maintenance of pregnancy. Early studies of endocrine regulation of expression of proteins secreted by uteri of pigs (uteroferrin, ACP5; Knight et al 1973) and sheep (serine protease inhibitors or uterine milk proteins; Moffat et al 1987) revealed a requirement for longterm treatment with P 4 , indicating that effects of P 4 were not mediated by a 'classical' steroid receptor-type mechanism of action. Based on current evidence, longterm treatment with P 4 is required in order to downregulate PGR as a prerequisite to expression of proteins such as uteroferrin and uterine milk proteins in response to one or more progestamedins (Spencer et al 1999, Spencer & Bazer 2002.…”

Section: Introductionmentioning

confidence: 99%

Comparative aspects of implantation

Bazer

Spencer²,

Johnson³

et al. 2009

337

285

Uterine receptivity to implantation of blastocysts in mammals includes hatching from zona pellucida, precontact with uterine luminal (LE) and superficial glandular (sGE) epithelia and orientation of blastocyst, apposition between trophectoderm and uterine LE and sGE, adhesion of trophectoderm to uterine LE/sGE, and, in some species, limited or extensive invasion into the endometrial stroma and induction of decidualization of stromal cells. These peri-implantation events are prerequisites for pregnancy recognition signaling, implantation, and placentation required for fetal-placental growth and development through the remainder of pregnancy. Although there is a range of strategies for implantation in mammals, a common feature is the requirement for progesterone (P 4 ) to downregulate expression of its receptors in uterine epithelia and P 4 prior to implantation events. P 4 then mediates its effects via growth factors expressed by stromal cells in most species; however, uterine luminal epithelium may express a growth factor in response to P 4 and/or estrogens in species with a true epitheliochorial placenta. There is also compelling evidence that uterine receptivity to implantation involves temporal and cell-specific expression of interferon (IFN)-stimulated genes that may be induced directly by an IFN or induced by P 4 and stimulated by an IFN. These genes have many roles including nutrient transport, cellular remodeling, angiogenesis and relaxation of vascular tissues, cell proliferation and migration, establishment of an antiviral state, and protection of conceptus tissues from challenges by the maternal immune cells.