Expression In Duodenum Research Articles

Effects of bamboo vinegar powder on growth performance and mRNA expression levels of interleukin-10, interleukin-22, and interleukin-25 in immune organs of weaned piglets.

The aim of this study was to explore the effects of bamboo vinegar powder on growth performance, diarrhea situation and mRNA expression levels of cytokines i.e., interleukin-10 (IL-10), interleukin-22 (IL-22), and interleukin-25 (IL-25) in immune organs of weaned piglets, and to accumulate theoretical data for the application of bamboo vinegar powder in weaned piglet production. Forty-five crossbred (Duroc × Landrace × Yorkshire, all male) weaned piglets with similar body weight (6.74 ± 0.17 kg) at 31 days of age were randomly assigned to 5 treatments with 3 replicates per treatment and 3 piglets in each replicate. The five treatments were as follows: CON (a basal diet), ANT (the basal diet + 0.12% antibiotics), BV1 (the basal diet + 0.1% bamboo vinegar powder), BV5 (the basal diet + 0.5% bamboo vinegar powder), BV10 (the basal diet + 1.0% bamboo vinegar powder). This experiment lasted 35 days. The growth performance and diarrhea situation were recorded. The relative mRNA expression levels of IL-10, IL-22 and IL-25 in liver, spleen, duodenum and mesenteric lymph nodes were detected by real-time PCR. Feed: gain of BV5 was significantly lower than that of CON (P < 0.05). In comparison with CON, diarrhea rate and diarrhea index of BV1 and BV5 all tended to decrease (P < 0.1). Compared with CON, mRNA expression level of IL-10 in liver of ANT tended to be lower (P < 0.1) and these of BV1, BV5 and BV10 were significantly reduced (P < 0.05). The mRNA expression levels of IL-10 in duodenum of ANT, BV1, BV5 and BV10 were all lower than those of CON, of which BV10 had significantly decreased IL-10 mRNA expression in duodenum (P < 0.05). The mRNA expression levels of IL-22 in duodenum of ANT, BV1, BV5 and BV10 all tended to be inhibited compared with CON (P < 0.1). With the increase of bamboo vinegar powder dosage, mRNA expression levels of IL-25 in spleen and mesenteric lymph nodes of BV1, BV5 and BV10 tended to be up-regulated. Overall, bamboo vinegar powder could improve growth performance, and regulate mRNA expression levels of IL-10, IL-22 and IL-25 in immune organs of weaned piglets. The dosage at 0.5% showed optimum effects.

Molecular Cloning, Sequence Analysis and Tissue Expression of Porcine R-Spondin2

The R-spondin 2 (Rspo2) belongs to the Rspo family, which is a cluster of secreted molecules possessing pleiotropic functions in development and stem cell growth by strongly enhancing Wnt signaling activation. In this study, porcine Rspo2 (pRspo2) was amplified from cDNA derived from porcine brain tissue. DNA sequencing result indicates that the open reading frame (ORF) of pRspo2 consists of 732 base pairs (bp), encodes 243 amino acids protein with a putative molecular weight of 28.19 kDa and is high identity to those of horse (98%), cattle (98%), human (96%) and rat (92%). pRspo2 is highly expressed in the brain tissue, whereas with comparatively lower level of expression in duodenum, thymus, liver, lung, lymph node, kidney and ileum tissues, which is characterized by reverse transcriptionpolymerase chain reaction (RT-PCR) analysis. All the results above will provide the fundamental research on the pleiotropic functions of pRspo2.

Intermittent fasting modulates IgA levels in the small intestine under intense stress: a mouse model.

Intermittent fasting prolongs the lifespan and unlike intense stress provides health benefits. Given the role of the immunoglobulin A (IgA) in the intestinal homeostasis, the aim of this study was to assess the impact of intermittent fasting plus intense stress on secretory IgA (SIgA) production and other mucosal parameters in the duodenum and ileum. Two groups of six mice, with intermittent fasting or fed ad libitum for 12weeks, were submitted to a session of intense stress by a bout of forced swimming. Unstressed ad libitum fed or intermittently fasted groups were included as controls. After sacrifice, we evaluated intestinal SIgA and plasma adrenal hormones, lamina propria IgA+ plasma-cells, mRNA expression of polymeric immunoglobulin receptor, α- and J-chains in the liver and intestinal mucosa, as well as pro- (tumor necrosis factor-α, interleukin-6 and Interferon-γ) and anti- (interleukin-2, -4, -10 and transforming growth factor-β) inflammatory cytokines in mucosal samples. Under intense stress, intermittent fasting down- or up-modulated the levels of most parameters in the duodenum and ileum, respectively while up-regulated corticosterone levels without affecting epinephrine. Our data suggest intermittent fasting plus intense stress elicited neuroendocrine pathways that differentially controlled IgA and pIgR expression in duodenum and ileum. These findings provide experimental foundations for a presumable impact of intermittent fasting under intense stress on the intestinal homeostasis or inflammation by triggering or reducing the IgA production in ileum or duodenum respectively.

Immunohistochemical Detection of Gut‐Brain‐Axis Markers along the Gastrointestinal Tract of Formula‐Fed Piglets

Intestinal neurotransmitters and hormones modulate neuronal signaling across the gut-brain-axis (GBA) and provide a means whereby dietary components and the gut microbiota communicate with the brain to influence behavior and cognition. However, little is known about the expression of GBA markers in the neonatal gastrointestinal (GI) tract. Herein, regional differences in the expression of serotonin (5'HT), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP) were studied in piglets. Two-day-old, vaginally-delivered male piglets (n=24) were artificially-reared using milk replacer customized to meet piglet nutrient requirements. On d31, duodenum, ileum, ascending colon samples were collected and the expression of 5'HT, VIP and TH were assessed by immunohistochemistry and confocal microscopy. Markers of the GBA were expressed as a proportion of either total cell number (5'HT) or area of positive staining in µm2 (TH and VIP). The ratios of 5'HT positive-to-enterochromaffin (EC) positive cells (P=0.02), 5'HT positive- (P<0.0001) and EC positive-to-total cell number (P=0.005), as determined by DAPI-positive cells, were higher in the duodenum than all other regions. Also, TH-positive expression tended to be higher (P=0.09) in the duodenum than the ileum, and VIP-positive expression in duodenum and ileum was higher (P=0.003) than in the ascending colon. In conclusion, for the markers assessed herein, a proximal-to-distal gradient of GBA marker expression exists along the GI tract of the piglet. Supported by Mead Johnson Nutrition.

Perinatal administration of a bitter tastant influences gene expression in chicken palate and duodenum.

Bitter taste receptors (Tas2rs) and downstream effectors are responsible for mediating bitterness perception and regulation of food choice in mammals. Using RT-PCR, we demonstrated the expression of three Tas2rs and taste signal transduction molecules, α-gustducin, PLCβ2, and TRPM5, in the palate, tongue, and gastrointestinal tract sections in chicken. The bitter tastant quinine activates all three chicken Tas2rs in vitro as shown using calcium-imaging assays of transfected cells. Administration of quinine postnatally or perinatally (both pre- and posthatch) to chickens increased the expression of Tas2r genes in the palate by 6.45-fold (ggTas2r1 postnatal treatment), 4.86-fold (ggTas2r1 perinatal treatment), and 4.48-fold (ggTas2r7 postnatal treatment) compared to the genes' expression in the naı̈ve group respectively, and affected taste related gene expression in the duodenum. Whereas no-choice intake of quinine solution was not significantly lower than that of water in naı̈ve chicks, the treatment groups postnatal, prenatal, and perinatal showed significantly lower intake of quinine by 56.1, 47.7, and 50.2%, respectively, suggesting a possible trend toward sensitization. These results open new venues toward unraveling the formative stages shaping food intake and nutrition in chicken.

Fructus ligustri lucidi Ethanol Extract Improves Bone Mineral Density and Properties Through Modulating Calcium Absorption-Related Gene Expression in Kidney and Duodenum of Growing Rats

Optimizing peak bone mass in early life is one of key preventive strategies against osteoporosis. Fructus ligustri lucidi (FLL), the fruit of Ligustrum lucidum Ait., is a commonly prescribed herb in many kidney-tonifying traditional Chinese medicinal formulas to alleviate osteoporosis. Previously, FLL extracts have been shown to have osteoprotective effect in aged or ovariectomized rats. In the present study, we investigated the effects of FLL ethanol extract on bone mineral density (BMD) and mechanical properties in growing male rats and explored the underlying mechanisms. Male weaning Sprague-Dawley rats were randomized into four groups and orally administrated for 4 months an AIN-93G formula-based diet supplementing with different doses of FLL ethanol extract (0.40, 0.65, and 0.90 %) or vehicle control, respectively. Then calcium balance, serum level of Ca, P, 25(OH)2D3, 1,25(OH)2D3, osteocalcin (OCN), C-terminal telopeptide of type I collagen (CTX-I), and parathyroid hormone, bone microarchitecture, and calcium absorption-related genes expression in duodenum and kidney were analyzed. The results demonstrated that FLL ethanol extract increased BMD of growing rats and improved their bone microarchitecture and mechanical properties. FLL ethanol extract altered bone turnover, as evidenced by increasing a bone formation maker, OCN, and decreasing a bone resorption maker, CTX-I. Intriguingly, both Ca absorption and Ca retention rate were elevated by FLL ethanol extract treatment, possibly through the mechanisms of up-regulating the transcriptions of calcitropic genes in kidney (1α-hydroxylase) and duodenum (vitamin D receptor, calcium transporter calbindin-D9k, and transient receptor potential vanilloid 6). In conclusion, FLL ethanol extract increased bone mass gain and improved bone properties via modulating bone turnover and up-regulating calcium absorption-related gene expression in kidney and duodenum, which could then activate 1,25(OH)2D3-dependent calcium transport in male growing rats.

Chronic delta‐9‐tetrahydrocannabinol differentially regulates gene expression in duodenum of Simian immunodeficiency virus‐infected macaques

Previously we demonstrated that chronic Δ9‐tetrahydrocannabinol (THC) administration attenuates classic markers of simian immunodeficiency virus (SIV) disease progression, decreases early mortality and attenuates inflammation in SIV‐infected rhesus macaques. The mechanisms involved in amelioration of disease progression are unknown. The gut is an important target for HIV/SIV infection. We hypothesized that modulation of genes involved in mucosal immunity, viral replication and barrier function may contribute to THC‐modulated disease progression. We examined the impact of chronic THC administration on the duodenal transcriptome. Using GeneGO, duodenal gene expression of vehicle‐ or THC‐administered SIV‐infected (THC/SIV) macaques was compared to uninfected naive macaques. Analysis of the 188 genes differentially regulated by THC using STRING database identified their role in antiviral and stress responses and gut barrier and immune function. THC/SIV gene expression ≥ 1.5‐fold or ≤ 0.5‐fold was verified by RT‐qPCR and Western blot. THC significantly increased mRNA expression of antiviral MX‐1, protein expression of IFIT1 and HSPA2 and attenuated the increase of IGJ protein. These results suggest that THC‐mediated changes in gut gene expression may contribute to functional modification of gut immunity and participate in modulation of disease progression. Supported by DA020419, DA030053

Soy isoflavones increase bone mineral density without altering markers of whole body vitamin D or calcium metabolism in mice

The soy isoflavone genistein enhances the biological activity of the vitamin D (VD) metabolite 1,25 dihydroxyvitamin D (1,25D) in cultured cells by inhibiting CYP24‐mediated degradation of the hormone. We examined if similar effects can be recapitulated in vivo to improve calcium and bone metabolism. Weanling male B6D2F1 mice were fed AIN‐93G diets containing 50 or 400 IU VD with, or without, Novasoy® 400 soy isoflavone concentrate (added to provide 250 mg genistein/kg diet) until 13 weeks of age. Bone mineral density (BMD) was measured by DEXA. Serum VD metabolites were measured by RIA. Gene expression in duodenum and kidney was measured by RT‐PCR. Higher dietary VD intake increased serum 25 hydroxyvitamin D (25D) from levels viewed as adequate (61 ± 6 nM) to optimal (164 ± 10 nM) for human health but this had no impact on either BMD or molecular indices of calcium metabolism. In contrast, isoflavones increased both serum 25D and femur BMD by 15% (p &lt; 0.01). However, neither serum 1,25D nor tissue gene expression (e.g. duodenal calbindin D9K, TRPV6; renal calbindin D9K or D28K, TRPV5) was influenced by isoflavones. Our data show that the beneficial effect of soy isoflavones on bone that we observed is independent of their ability to modulate whole body VD or calcium metabolism and suggest a direct effect of isoflavones on bone formation or turnover. We thank ADM for Novasoy® 400. Funding: Purdue‐UAB Botanicals Center Pilot Grant.Grant Funding Source: Purdue‐UAB Botanicals Center Pilot Grant

Onecut-2 knockout mice fail to thrive during early postnatal period and have altered patterns of gene expression in small intestine

Ablation of the mouse genes for Onecut-2 and Onecut-3 was reported previously, but characterization of the resulting knockout mice was focused on in utero development, principally embryonic development of liver and pancreas. Here we examined postnatal development of these Onecut knockout mice, especially the critical period before weaning. Onecut-3 knockout mice develop normally during this period. However, Onecut-2 knockout mice fail to thrive, lagging behind their littermates in size and weight. By postnatal day (d)19, they are consistently 25-30% smaller. Onecut-2 knockout mice also have a much higher level of mortality before weaning, with only approximately 70% survival. Interestingly, Onecut-2 knockout mice that are heterozygous for the Onecut-3 knockout allele are diminished even further in their ability to thrive. They are approximately 50-60% as large as their normal-sized littermates at d19, and less than half of these mice survive to weaning. As reported previously, the Onecut-2/Onecut-3 double knockout is a perinatal lethal. Microarray technology was used to determine the effect of Onecut-2 ablation on gene expression in duodenum, whose epithelium has among the highest levels of Onecut-2. A subset of intestinally expressed genes showed dramatically altered patterns of expression. Many of these genes encode proteins associated with the epithelial membrane, including many involved in transport and metabolism. Previously, we reported that Onecut-2 was critical to temporal regulation of the adenosine deaminase gene in duodenum. Many of the genes with altered patterns of expression in Onecut-2 knockout mouse duodenum displayed changes in the timing of gene expression.

Genetic Analysis of Lrp5 Function in Osteoblast Progenitors

The low-density lipoprotein receptor-related protein (Lrp)-5 regulates osteoblast proliferation and bone formation through its expression in duodenum by modifying the gut serotonin-bone endocrine axis. However, its direct role, if any, in osteoblast progenitor cells has not been studied thus far. Here, we show that mice with a Dermo1-Cre-mediated disruption of Lrp5 in osteoblast progenitor cells have normal embryonic skeletogenesis and normal skeletal growth and development postnatally. Histomorphometric analysis of 3-month-old adult mice revealed normal osteoblast numbers, bone formation rate, and bone mass in Lrp5(Dermo)(-/-) mice. In addition, analysis of two osteoporosis pseudoglioma (OPPG) patients revealed a three- to fivefold increase in their serum serotonin levels compared to age-matched controls. These results rule out a direct function of Lrp5 in osteoblast progenitor cells and add further support to the notion that dysregulation of serotonin synthesis is involved in bone mass abnormalities observed in OPPG patients.

Responses of mRNA expression of PepT1 in small intestine to graded duodenal soybean small peptides infusion in lactating goats.

To study the effect of circulation small peptides concentration on mRNA expression in small intestine, graded amount of soybean small peptides (SSP) were infused into lactating goats through duodenal fistulas. Peptide-bound amino acid (PBAA) concentration in arterial plasma and the mRNA expression of PepT1 was detected in the current study. The results showed that concentrations of all peptidebound amino acids (PBAA) increased and the activity of PepT1 in duodenum tissue was enhanced by SSP infusion. The PepT1expression in duodenum tissue was significantly increased with the increment of amounts of SSP infusion (P<0.05). That in ileum tissue was increased with the increment of the amounts of SSP infusion; the increment of Pep T1 expression was significant only in the 180 g/d treatment (P<0.05). mRNA abundance of PepT1 in jejunum tissue was 1.1 to 1.8 to 2.4 times in SSP infusion group as compared with the control group. In the 120 and 180 g/d treatment, the difference of PepT1 expression in jejunum was significant (P<0.05). The data suggested Pep T1 expression in duodenum, ileum and jejunum tissue was enhanced by an increase in circulation small peptide concentration, and the duodenum might be a main position of small peptides absorption in intestine.

Tissue distribution of CYP3A29 mRNA expression in Bama miniature pig by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR)

Pig or minipig cytochrome P450 (CYP) 3A isozymes have been proven to be a good model of human drug metabolism, and human CYP3A seems to be well modelled by pig or minipig CYP3A29.We studied CYP3A29 mRNA expression in ten tissues (liver, duodenum, kidney, adrenal gland, skin, brain, lung, testis, uterus and ovary) in different age groups of Bama miniature pig by real-time reverse transcriptase-polymerase chain reaction (RT-PCR).In adult pig (4 and 6 months old), the most relative expression by normalization to β-actin of CYP3A29 mRNAs of tissues is in liver; then in duodenum, skin and kidney. Values of CYP3A29 in the extrahepatic tissues except for duodenum are very low compared with that in liver.In new-borns the mean CYP3A29 expression in duodenum was higher than that in liver, and the expression in skin was very low while high in 40 days, 4 months and 6 months age groups. For different ages, the increased CYP3A29 expression in liver and duodenum was detected with age. The effective CYP3A29 induction in liver was also detected by rifampin oral intubation. Apparent interindividual variability of CYP3A29 mRNA expression in Bama miniature pigs was detected.This work will broaden the understanding of the physiological functions of CYP3A29 in miniature pig, and promote Bama miniature pig’s application in pharmacological and toxicological studies.

Host response to simultaneous infections with Eimeria acervulina, maxima and tenella: A cumulation of single responses

It is well known that broilers may be infected by different Eimeria strains at the same time and that different species infect specific parts of the gut. Cell mediated responses play a major role in the immune response in broilers after infection with Eimeria species. The cell mediated responses could be intestinal site specific and if this site specific cell mediated responses differ when other parts of the intestine are infected is unknown. To investigate this in the Eimeria infection model we analyzed the cell mediated responses to an infection with a single Eimeria species and with a mixture of different species of Eimeria such as E. acervulina, E. maxima or E. tenella in the duodenum, jejunum and caecum. The immune parameters we measured were intestinal T-cell and macrophage population dynamics as well as local cytokine mRNA expression. These parameters were related to the amount of Eimeria DNA that was measured in the intestine with an Eimeria strain specific quantitative PCR. The results showed that the strongest immune response was induced in the specific part of the intestine that was affected by each Eimeria strain. An E. acervulina infection mainly induced a duodenal CD8 + T-cell and macrophage response as well as an increased IL-2, IL-4, IL-8, IL-10, and INF-γ response. An E. maxima infection mainly induced a CD4 + T-cell and macrophage response but also an increased IL-4, IL-8, and very strong INF-γ (300-fold) expression in duodenum and jejunum. E. tenella induced a CD4 + T-cell, macrophage response and an increase in the IL-2, IL-4, IL-8, IL-10, IL-18 and INF-γ response in the caecum. The infection with a mixture of Eimeria species resulted in responses per intestinal segment that were similar to that observed following the single species infection. No synergistic or competitive effects were thus observed following a primary infection with a mixture of Eimeria species. In contrast, we observed an accumulation of the local effects of the single infections.

Indazole-Based Liver X Receptor (LXR) Modulators with Maintained Atherosclerotic Lesion Reduction Activity but Diminished Stimulation of Hepatic Triglyceride Synthesis

A series of substituted 2-benzyl-3-aryl-7-trifluoromethylindazoles were prepared as LXR modulators. These compounds were partial agonists in transactivation assays when compared to 1 (T0901317) and were slightly weaker with respect to potency and efficacy on LXRalpha than on LXRbeta. Lead compounds in this series 12 (WAY-252623) and 13 (WAY-214950) showed less lipid accumulation in HepG2 cells than potent full agonists 1 and 3 (WAY-254011) but were comparable in efficacy to 1 and 3 with respect to cholesterol efflux in THP-1 foam cells, albeit weaker in potency. Compound 13 reduced aortic lesion area in LDLR knockout mice equivalently to 3 or positive control 2 (GW3965). In a 7-day hamster model, compound 13 showed a lesser propensity for plasma TG elevation than 3, when the compounds were compared at doses in which they elevated ABCA1 and ABCG1 gene expression in duodenum and liver at equal levels. In contrast to results previously published for 2, the lack of TG effect of 13 correlated with its inability to increase liver fatty acid synthase (FAS) gene expression, which was up-regulated 4-fold by 3. These results suggest indazoles such as 13 may have an improved profile for potential use as a therapeutic agent.

Isx Participates in the Maintenance of Vitamin A Metabolism by Regulation of β-Carotene 15,15′-Monooxygenase (Bcmo1) Expression

Isx (intestine specific homeobox) is an intestine-specific transcription factor. To elucidate its physiological function, we generated Isx-deficient mice by knocking in the beta-galactosidase gene (LacZ) in the Isx locus (IsxLacZ/LacZ mice). LacZ staining of heterozygous (IsxLacZ/+) mice revealed that Isx was expressed abundantly in intestinal epithelial cells from duodenum to proximal colon. Quantitative mRNA expression profiling of duodenum and jejunum showed that beta-carotene 15,15'-monooxygenase (EC1.14.99.36 Bcmo1) and the class B type I scavenger receptor, which are involved in vitamin A synthesis and carotenoid uptake, respectively, were drastically increased in IsxLacZ/LacZ mice. Although mild vitamin A deficiency decreased Isx expression in duodenum of wild-type (Isx+/+) mice, severe vitamin A deficiency decreased Isx mRNA expression in both duodenum and jejunum of Isx+/+ mice. On the other hand, vitamin A deficiency increased Bcmo1 expression in both duodenum and jejunum of Isx+/+ mice. However, Bcmo1 expression was not increased in duodenum of IsxLacZ/LacZ mice by mild vitamin A deficiency. These data suggest that Isx participates in the maintenance of vitamin A metabolism by regulating Bcmo1 expression in the intestine.

Effect of erythropoietin on hepcidin, DMT1 with IRE, and hephaestin gene expression in duodenum of rats

Erythropoietin (Epo) is the central regulator of red blood cell production and can stimulate proliferation and differentiation of erythroid progenitor cells. Now, recombinant human erythropoietin (rHuEpo) is widely used in patients with renal disease, chronic anemia, and iron deficiency of early childhood. It has been reported that the enhanced erythropoiesis associated with erythropoietin therapy increases intestinal iron absorption, but the molecular mechanisms underlying are unknown. Therefore, we have investigated the effect of rHuEpo on duodenal iron transport protein synthesis in rats. Male Sprague-Dawley rats weighing 250 g were randomly divided into two groups: (1) rHuEpo injection group (rHuEpo, 500 IU/day, s.c.), and (2) control group (injection of the same volume of saline). After 3 days injection, blood parameters, serum iron status, and non-heme iron concentrations in the liver and duodenum were examined at the fifth day. The mRNA levels and protein synthesis of duodenal divalent metal transporter 1 (DMT1), ferroportin 1 (FPN1), and hephaestin (Hp) were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis. Hepatic hepcidin mRNA expression was analyzed by RT-PCR. rHuEpo injection significantly stimulated erythropoiesis and decreased serum iron status, non-heme iron concentrations in the liver and duodenum. DMT1 (+IRE) and Hp expression in duodenum were increased significantly. However, DMT1 (-IRE) and FPN1 expression had no apparent change. Hepatic hepcidin mRNA expression was decreased dramatically, reaching an almost undetectable level in rHuEpo-treated rats. rHuEpo administration improved the duodenal iron absorption by increasing the expression of DMT1 (+IRE) and Hp.

Down-regulated in adenoma mediates apical Cl-/HCO3− exchange in rabbit, rat, and human duodenum

Duodenal bicarbonate secretion is in part mediated by an apical Cl-/HCO3- exchanger of unknown molecular nature. The recently discovered dra (down-regulated in adenoma) gene encodes a transport protein (DRA) for SO4(2-), Cl-, and HCO3-. The aim of this study was to investigate whether DRA may be the duodenal apical Cl-/HCO3- exchanger. DRA, Na+/H+ exchanger (NHE) isoform 3, and anion exchanger isoform (AE) 2 messenger RNA expression levels were studied in rat, rabbit, and human gastrointestinal tract by semiquantitative reverse-transcription polymerase chain reaction and in situ hybridization (DRA in human intestine). The subcellular localization of DRA was determined by Western analysis and immunohistochemistry. Using rabbit and rat duodenal brush border membrane vesicles, anion exchange characteristics were investigated. DRA expression was high in duodenum and colon of all species, whereas NHE3 messenger RNA expression was low in duodenum and high in colon. Western analysis and immunohistochemistry showed an apical localization for DRA. Rabbit and rat duodenal brush border membrane vesicles showed 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid-sensitive Cl-/Cl-, HCO3-/Cl-, SO4(2-)/Cl-, and Cl-/SO4(2-) exchange, with evidence for one major brush border membrane Cl-/anion exchanger, an affinity for Cl- > HCO3-, and a much higher affinity for SO4(2-) in rat than rabbit. The strong predominance of DRA over NHE3 and NHE2 expression in duodenum was paralleled by much higher Cl-/HCO3- than Na+/H+ exchange rates in brush border membrane vesicles and likely explains the high duodenal HCO3- secretory rates. These data suggest that DRA is the major apical anion exchanger in the duodenum as well as the colon and the likely transport protein for duodenal electroneutral HCO3- secretion.

Effects of metformin on SGLT1, GLUT2, and GLUT5 hexose transporter gene expression in small intestine from rats

The effect of the antihyperglycaemic agent metformin was studied on gene expression of the energy-dependent sodium-hexose cotransporter (SGLT1) and the facilitative hexose transporters GLUT2 and GLUT5 in rat intestine. Metformin treatment (125 mg/kg body wt. twice daily for a period of 3 days) significantly increased SGLT1 gene expression in duodenum and jejunum. GLUT5 gene expression was increased by metformin treatment only in the jejunum. Gene expression of GLUT2 in the intestine was not significantly affected by metformin treatment. This increase in transporter gene expression offers the potential for increases in hexose uptake at the brush border membrane, and may compensate for other effects of the drug that have been suggested to decrease glucose uptake by SGLT1, as well as for metformin stimulation of glucose utilization by the intestinal mucosa.

The baboon expresses the calbindin‐D9k gene in intestine but not in uterus and placenta: Implication for conservation of the gene in primates

Expression of the Calbindin-D9k (CaBP-9k) gene was studied in the baboon. Northern blot analysis using a human CaBP-9k cDNA probe detected expression in duodenum but not in uterus and placenta. Reverse transcription/polymerase chain reaction (RT/PCR) confirmed this expression pattern and indicated a high degree of identity between the baboon and human CaBP-9k mRNAs. PCR was employed to amplify the intron A region of the baboon CaBP-9k gene using human-derived primers and baboon genomic DNA. The baboon intron was closely related to the human CaBP-9k intron A, including the presence a complete Alu-repetitive element. Most significantly, a 13 nucleotide long element at the 5' end of the baboon intron matched exactly the human sequence. This element represents a nonfunctional variation of an estrogen response element found at the same location in the rat CaBP-9k gene. The rat element functions as an enhancer and mediates uterine and possibly placental CaBP-9k expression in the rat and probably most other mammals. The finding of a modified ERE in baboon as in human suggests that during primate evolution the expression of this mammalian-specific gene has been eliminated in uterus and placenta. This scenario raises the question of the role of CaBP-9k in these reproductive tissues.