Erythropoietin mRNA expression in pig embryos

Abstract

To address whether altered erythropoietin (EPO) synthesis might be involved in prenatal pig mortality, studies were conducted to measure porcine embryonic EPO mRNA expression during early gestation (days 24-40). Three pig models differing in embryonic survival from days 24-40 were investigated: intact white crossbred gilts (INT), white crossbred gilts that were unilaterally hysterectomized-ovariectomized before puberty and whose pregnant uterus constituted a crowded environment (UHO), and prolific, intact Meishan gilts (ME). A partial cDNA for porcine EPO, developed via reverse transcription and polymerase chain reaction procedures was used to generate a 32P-labeled probe for use in Northern analyses. In an initial study, embryonic liver EPO mRNA was greatest on day 24, decreased by day 30 (P<0.01), and was barely detectable by day 40. EPO mRNA expression was not influenced by pig model. Placental EPO mRNA expression was detectable in only 4 of 53 placentae examined. In a second study at day 35 of gestation, embryonic liver EPO mRNA expression was measured in the same three pig models and in two embryos of divergent weights from each gilt. Meishan embryos had lower (P<0.01) plasma immunoassayable EPO concentrations (P=0.04) and higher survival rates (87+/-2.7%) at day 35 than did white crossbred embryos (75+/-5%). Liver EPO mRNA expression did not differ among animal models, nor did plasma EPO or tissue EPO mRNA expression differ between large and small embryos. There was no apparent relationship between embryonic development, measured as embryonic and placental size, and plasma EPO concentrations or liver EPO mRNA expression. These results indicate that at the gestational ages examined, the embryonic liver is one source of plasma erythropoietin and suggest that at the ages sampled, EPO is not a limiting factor in embryonic development.

Characterization of porcine uterine estrogen sulfotransferase

“…Northern blot analysis was performed using 30 g of total RNA from endometrium of days 10, 13, and 15 cyclic gilts and days 10, 13, 15, 20, 30, and 40 pregnant White composite gilts (n = 3-4 gilts per day) as described previously [14,15]. Total RNA was electrophoresed in 1.5% agarose gels prepared in MOPS (3-[N-morpholino] propane-sulfonic acid)/formaldehyde buffer, and the gels were then blotted onto Hybond-N nylon membrane (Amersham Life Science, Buckinghamshire, England).…”

“…Digested and dephosphorylated DNA fragments were precipitated, reconstituted with sterile water, and subcloned into SK vector previously digested with BamHI. Colonies were replicated onto membranes and then screened for microsatellites using a (GT) 14 oligonucleotide probe. GT probe was endlabeled with [␥ 32 P]dATP and the membranes were hybridized with Rapid-hyb (Ambion, Austin, TX) containing 1 × 10 6 cpm/mL of radiolabeled probe at 58 • C overnight.…”

A substitution within erythropoietin receptor gene D1 domain associated with litter size in Beijing Black pig, Sus scrofa

“…Furthermore, fetal erythropoiesis in Meishan gilts was accelerated compared to White crossbred gilts, suggesting that faster development of mature blood cells could be beneficial to fetal survival in swine (Vallet et al 2003). However, liver expression levels of EPO (Klemcke et al 2001) and of EPOR (Pearson et al 2000) were not Mean first parity TNB values without a common superscript were significantly different (P < 0.05). A,B Mean values within a column without a common superscript were significantly different (P < 0.01).…”

Placental function in development and disease

“…First, the invasive trophoblast population produces angiogenic factors and vasodilators and, in some species, actually invades the arteries also to increase blood flow to the implantation site . Second, the placenta has been shown, in several species, to produce hormones that stimulate the pregnancy associated increase in maternal blood cell production and blood volume (Conrad et al 1996;Kim et al 2001;Klemcke et al 2001;Zhou et al 2002Zhou et al , 2005. Third, the placenta produces several metabolic hormones, such as placental lactogens and placental growth hormone, that can alter insulin production and promote insulin resistance in maternal tissues, resulting in increased glucose availability to the fetus (Soares et al 1998;Linzer and Fisher 1999).…”