Immunolocalization of epidermal growth factor (EGF) and EGF receptors in the porcine upper gastrointestinal tract.

The factors controlling growth and maturation in the porcine gastrointestinal tract are not well understood. Epidermal growth factor (EGF) is a polypeptide that has been implicated in the control of gastrointestinal tract growth, maturation, and protection in other species. Immunoreactive EGF (IR-EGF) and EGF receptors (EGF-R) were histochemically identified in formalin-fixed tissues of the upper digestive tract of 1-, 3-, 7-, 14-, 21-, and 28-day-old pigs. The ductal epithelium consistently contained IR-EGF in the parotid salivary gland of pigs of all ages and in the mandibular salivary gland in pigs greater than or equal to 7 days old. Immunoreactive EGF was detected in the mucosal epithelium of the esophagus and nonglandular portion of the stomach, and in the pancreas and liver in all pigs. Gastric gland IR-EGF was inconsistently detected in pigs less than 14 days old and was consistently observed in all older pigs. Enterocyte EGF immunoreactivity was usually weak and was variably detected in the duodenum of pigs less than or equal to 7 days old and in the jejunum of pigs less than or equal to 14 days old, but was consistently observed in older pigs. Ileal immunoreactivity was erratic. Immunoreactive EGF-R were identified in the esophageal epithelium of all pigs, and in the nonglandular gastric and glandular gastric mucosa of all pigs, except for two 7-day-old pigs and one 7-day-old pig, respectively. Immunoreactive EGF-R were detected in the duodenal, jejunal, and ileal enterocytes of pigs of all ages examined.     

Changes in oestrogen,progesterone and epidermal growth factor receptor concentrations and affinities during the oestrous cycle in the normal mammary gland and uterus of dogs

Changes in the concentrations and affinities of receptors for oestrogen (ER), progesterone (PR) and epidermal growth factor (EGF-R) were studied in mammary glands of healthy bitches with regard to age, the location in the mammary chain and the stage of the oestrous cycle. Uterus was used as the reference tissue for the evaluation of steroid receptors. Mammary and uterine samples from 7 healthy bitches were taken at five stages of the oestrous cycle in such a way that all the locations in the mammary chain were represented at each stage of the cycle (10 samples/dog). ER, PR and EGF-R were detected by biochemical assays using increasing concentrations of tritiated (steroids) or iodinated (EGF) ligands. A significant direct correlation was found between the ER and PR concentrations for mammary and uterine samples. No significant correlation was found between the steroid receptors and EGF-R concentrations. Mammary ER concentrations were significantly higher in bitches of 5 years of age or older than in younger ones; in posterior glands (4th and 5th pairs) than in anterior glands; and in the mid-luteal phase. Mammary PR did not vary significantly with age or location but was significantly lower in the early luteal phase than in other phases. A similar decrease in PR concentrations was observed in the uterus during the early luteal phase and uterine ER and PR concentrations were very low in the mid-luteal phase. Mammary EGF-R were not significantly higher in the early or mid-luteal phase than in pro-oestrus or anoestrus.The differences observed between the uterine and mammary steroid receptor concentrations during the oestrous cycle could be due to different mechanisms for regulating steroid receptor expression in the two tissues. Mammary EGF-R concentrations may be linked, as in other species, to cellular proliferation and/or to the serum progesterone concentrations.Abbreviations BSA bovine serum albumin - EGF epidermal growth factor - EGF-R receptor for epidermal growth factor - ER oestrogen receptor - K _d dissociation constant - LH luteinizing hormone - p probability of error - PR progesterone receptor     

Expression of epidermal growth factor receptor in plutonium-239-induced lung neoplasms in dogs.

The expression of epidermal growth factor receptor (EGF-R) was examined in canine lung tumors and in proliferative epithelial foci induced by plutonium-239 to determine if EGF-R was associated with specific neoplastic phenotypes or putative preneoplastic lesions. Seventeen (47%) of 36 canine lung tumors expressed EGF-R. Of these 17 tumors, three tumors hybridized with an erb-B RNA probe, which identified activated cell oncogenes. The expression of EGF-R was not correlated with tumor etiology, e.g., spontaneous versus radiation induced, but did correlate with specific histologic phenotypes. Nineteen (15%) of 127 proliferative epithelial foci in the canine lungs also expressed EGF-R. The phenotypic specificity demonstrated for EGF-R in canine lung tumors parallels that previously shown in human lung tumors. This finding, in addition to the identification of EGF-R in nonneoplastic proliferative lung lesions, indicates that radiation-induced lung tumors in the dog may be a useful animal model to investigate the role of EGF-R in lung carcinogenesis.     

The localization and expression of epidermal growth factor and epidermal growth factor receptor in bovine ovary during oestrous cycle

Epidermal growth factor (EGF) is one of the important regulatory factors of EGF family. EGF has been indicated to effectively inhibit the apoptosis of follicular cells, to promote the proliferation of granulosa cells and the maturation of oocytes, and to induce ovulation process via binding to epidermal growth factor receptor (EGFR). However, little is known about the distribution and expression of EGF and EGFR in cattle ovary especially during oestrous cycle. In this study, the localization and expression rule of EGF and EGFR in cattle ovaries of follicular phase and luteal phase at different time points in oestrous cycle were investigated by using IHC and real-time qPCR. The results showed that EGF and EGFR in cattle ovary were mainly expressed in granulosa cells, cumulus cells, oocytes, zona pellucida, follicular fluid and theca folliculi externa of follicles. The protein and mRNA expression of EGF/EGFR in follicles changed regularly with the follicular growth wave both in follicular and in luteal phase ovaries. In follicular phase ovaries, the protein expression of EGF and EGFR was higher in antral follicles than that of those in other follicles during follicular growth stage, and the mRNA expression of EGFR was also increased in stage of dominant follicle selection. However, in luteal phase ovaries, the growth of follicles was impeded during corpus luteum development under the action of progesterone secreted by granular lutein cell. The mRNA and protein expressions of EGF and EGFR in ovarian follicles during oestrous cycle indicate that they play a role in promoting follicular development in follicular growth waves and mediating the selection process of dominant follicles.     

Uterine NK cells produce epidermal growth factor in the murine pregnant uterus.

Uterine natural killer (uNK) cells belong to the large granular lymphocytes in the murine pregnant uterus and play essential roles in pregnancy success. We defined whether uNK cells can produce epidermal growth factor (EGF) important for implantation and embryo growth. The uNK cells were immunohistochemically positive for anti-EGF antibody especially during days 6 to 9 and at day 15 of pregnancy. Immunoreaction for EGF receptor was observed on the stromal cells in the metrial gland and trophoblasts in the placental labyrinth. EGF secretion (72.1 +/- 2.25 ng/10(40 cells) was noted in cultured uNK cells isolated from the metrial gland at day 15 of pregnancy. Treatment of anti-asialo-GM I antibody raised the level of EGF (129 +/- 21.5 ng/10(4) cells). These results suggest uNK cell can produce and release EGF for placental development.     

Course of epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I) in mammary secretions of the goat during end-pregnancy and early lactation

The epidermal growth factor (EGF) plays a crucial role in mammogenesis in many species. In ruminants, studies are limited, as EGF does not occur in peripheral plasma and specific analytical systems do not exist. Therefore a heterologous radioimmunoassay based on rhEGF was set up to monitor EGF in mammary gland secretions from goats during end-pregnancy and early lactation. IGF-I was measured with an established radioimmunoassay. Samples were collected from 13 goats for 25 days ante-partum and 25 days post-partum. Mammary gland secretions were obtained ante-partum by removing a small amount of the udder secretions (control half) or milking (stimulated half). Post-partum normal milk samples were collected. Blood samples were drawn by jugular venipuncture for the same period. EGF was found to occur in different molecular weight forms in the mammary glands. For routine measurements these proteins were extracted with acetone and not further separated. IGF-I and EGF concentrations in mammary secretions and similarly IGF-I in blood were high ante-partum and decreased slightly towards birth. IGF-I but not EGF is found in the peripheral plasma. Whereas IGF-I concentrations in blood were quite constant post-partum, IGF-I and EGF dropped in mammary secretions close to the detection limits. The decrease was more pronounced in the stimulated half than in the control half. The data support a synergistic role for EGF and IGF-I for mammogenesis. Both factors are further influenced by the milking stimulus and thus the functional state of the udder.     

Growth factor and receptor mRNA expression in the intestine of horses with large colon volvulus: a pilot study

REASONS FOR PERFORMING STUDY: Growth factors (GF) are important for maintenance and repair of intestinal mucosal structure and function, but there have been no studies investigating growth factor (GF) or growth factor receptor (GF-R) mRNA expression in the intestine of horses with large colon volvulus (LCV). OBJECTIVES: (1) To determine mRNA expression for epidermal growth factor (EGF), EGF receptor (EGF-R), insulin-like growth factor-I (IGF), IGF receptor (IGF-R), vascular endothelial growth factor (VEGF) and VEGF receptor (VEGF-R) in the intestine of horses with an LCV compared to normal intestine. (2) To measure the correlation between histological intestinal injury and mRNA expression. METHODS: In 5 horses, samples were collected from the mid-jejunum (small intestine, SI), pelvic flexure (PF) and right dorsal colon (RDC) prior to creation of the LCV (NORM), 1 h following creation of the LCV (ISCH) and 1 h following correction of the LCV (REPER). In 2 clinical cases of LCV, samples were collected from the PF and RDC. Samples were assessed histologically for the amount of intestinal injury. The mRNA expressions of growth factors and receptors were determined using qRT-PCR. RESULTS: VEGF and VEGF-R mRNA expression was greater in horses with an LCV compared to NORM. Expression of IGF-R mRNA increased in the SI during ISCH and REPER. CONCLUSION AND POTENTIAL RELEVANCE: The increase compared to NORM in VEGF and VEGF-R mRNA expression in horses with LCV may be important in early intestinal healing and may also explain, in part, the increase in vascular permeability in horses with a LCV. Expression of IGF and IGF-R in the SI warrants further investigation and may be important for understanding post operative complications in horses with SI lesions.     

Expression of epidermal growth factor receptor and vascular endothelial growth factor in malignant canine epithelial nasal tumours*

Epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) signalling pathways play a role in carcinogenesis. Inhibition of EGF receptor (EGFR) and of VEGF is effective in increasing the radiation responsiveness of neoplastic cells both in vitro and in human trials. In this study, immunohistochemical evaluation was employed to determine and characterize the potential protein expression levels and patterns of EGFR and VEGF in a variety of canine malignant epithelial nasal tumours. Of 24 malignant canine nasal tumours, 13 (54.2%) were positive for EGFR staining and 22 (91.7%) were positive for VEGF staining. The intensity and percentage of immunohistochemically positive neoplastic cells for EGFR varied. These findings indicate that EGFR and VEGF proteins were present in some malignant epithelial nasal tumours in the dogs, and therefore, it may be beneficial to treat canine patients with tumours that overexpress EGFR and VEGF with specific inhibitors in conjunction with radiation.     

Expression of Heparin‐Binding EGF‐Like Growth Factor (HB‐EGF) in Bovine Endometrium: Effects of HB‐EGF and Interferon‐τ on Prostaglandin Production

Heparin‐binding EGF‐like growth factor (HB‐EGF) regulates several cell functions by binding to its membrane receptor (ErbB1 and ErbB4). Experimental evidences suggest that HB‐EGF, prostaglandins (PGs) and interferon‐τ (IFN‐τ) regulate uterine function for pregnancy establishment in ruminants. In this study, the mRNA expressions of HB‐EGF, ErbB1 and ErbB4 in bovine endometrium and the effects of HB‐EGF and IFN‐τ on PGE2 and PGF2‐α production by endometrial cells were investigated. RT‐PCR analysis revealed that HB‐EGF mRNA was greater at the mid‐luteal stage than at the early and regressed luteal stages (p < 0.05). ErbB1 mRNA expression was greater at the mid‐ and late luteal stages than at the other luteal stages (p < 0.05). IFN‐τ increased the expression of HB‐EGF, ErbB1 and ErbB4 mRNA in epithelial cells (p < 0.05). HB‐EGF did not affect PGF2‐α or PGE2 production by bovine endometrial epithelial cells, but increased PGF2‐α and PGE2 production by bovine endometrial stromal cells (p < 0.05). IFN‐τ significantly decreased HB‐EGF‐stimulated PGF2‐α (p < 0.05), but not PGE2 (p > 0.05) production by stromal cells. These results indicate that HB‐EGF and its receptors expression changed in bovine endometrium throughout the oestrous cycle. IFN‐τ increased their expression in cultured endometrial cells. HB‐EGF and IFN‐τ have the ability to regulate PGs production by stromal cells and therefore may play a role in the local regulation of uterine function at the time of implantation in cattle.     

Vascular Endothelial (VEGF) and Epithelial Growth Factor (EGF) as Well as Platelet‐Activating Factor (PAF) and Receptors are Expressed in the Early Pregnant Canine Uterus

The aim of this study was to investigate the course of expression of platelet‐activating factor (PAF), PAF‐receptor (PAF‐R), epidermal growth factor (EGF), EGF‐R, vascular endothelial growth factor (VEGF), VEGF‐R1 and VEGF‐R2 in uterine tissue during canine pregnancy. For this purpose, 20 bitches were ovariohysterectomized at days 10–12 (n = 10), 18–25 (n = 5) and 28–45 (n = 5) days after mating, respectively. The pre‐implantation group was proven pregnant by embryo flushing of the uterus after the operation, the others by sonography. Five embryo negative, that is, non‐pregnant, bitches in diestrus (day 10–12) served as controls. Tissue samples from the uterus (placentation sites and horn width, respectively) were excised and snap‐frozen in liquid nitrogen after embedding in Tissue Tec^®. Extraction of mRNA for RT‐PCR was performed with Tri‐Reagent. In the embryos, mRNA from all factors except VEGF was detected. In the course of pregnancy, significantly higher expression of PAF and PAFR as well as VEGF and VEGFR2 during the pre‐implantation stage than in all other stages and a strong upregulation of EGF during implantation were characteristic. The course of EGF was in diametrical opposition to the course of the receptor. These results point towards an increased demand for VEGF, EGF and PAF during the earliest stages of canine pregnancy.     

IGF-I- and EGF-dependent DNA synthesis of porcine myoblasts is influenced by the dietary isoflavones genistein and daidzein

Soy-derived isoflavones have been reported to be specific inhibitors of protein tyrosine kinases like the type 1 insulin-like growth factor receptor (IGF-1R) and the epidermal growth factor receptor (EGFR). This study was conducted to investigate, whether IGF-I and EGF stimulate porcine myoblast growth and whether the responses are influenced by isoflavones. Satellite cell-born myoblasts derived from the semimembranosus muscle of newborn piglets were treated for 26h with IGF-I or EGF alone and in combination with genistein or daidzein. The DNA amount was measured and DNA synthesis was recorded as 6 h-[(3)H]thymidine incorporation during exponential growth in serum-free basal medium. IGF-I and EGF synergistically stimulated DNA synthesis of porcine myoblast with EGF causing a greater response. Genistein (100mumol/l) effectively reduced the growth factor-mediated DNA synthesis, which was associated with an inhibition of growth factor receptor protein expression. In response to daidzein no reduction in growth factor-mediated DNA synthesis was found. Daidzein (1; 10mumol/l) combined with IGF-I caused even a slight increase in DNA amount compared with the untreated control. The expression of the IGF-1R precursor protein was reduced with 10 and 100mumol/l daidzein, whereas the EGFR expression remained unchanged with daidzein. The results suggest that dietary isoflavones may interact with growth factor-induced stimulation of pig skeletal muscle growth.     

The distribution and immunolocalization of fibroblast growth factors (FGFs) in the rat oviduct during early pregnancy and the post-partum period

The mammalian oviduct provides a favourable environment for several reproductive processes, including ovum transport, sperm capacitation, fertilization and pre-implantation embryonic development. This environment is regulated by cyclic ovarian steroids, that is oestrogen, and growth factors. Fibroblast growth factors (FGFs) regulate the differentiation and growth of various cell types in the female genital tract. This study aimed to determine the localization of FGF1, FGF2, FGF receptor 1 (FGFR1) and 2 (FGFR2) in the rat oviduct, by immunohistochemistry, on day 5 of pregnancy and post-partum days 1, 3 and 5, and to demonstrate the possible functions of these proteins during early pregnancy and the post-partum period. On all examination days, cytoplasmic and nuclear FGF1 immunoreactivity was detected in the epithelium lining the infundibulum, ampulla and isthmus of the oviduct. Immunoreactivity was much stronger in the basal bodies of the cilia on the epithelium lining the infundibulum and ampulla. FGF1 immunoreactivity was also detected in stromal cells, myocytes and endothelial cells. Cytoplasmic FGF2 immunoreactivity was observed in the tunica muscularis, vascular myocytes and endothelial cells. While strong cytoplasmic FGF2 immunoreactions were observed in the stromal cells of the lamina propria, the luminal epithelium, some stromal cells and smooth muscle cells displayed a rather weak FGFR1 and FGFR2 immunoreactivity. Immunoreaction intensity did not differ between the periods examined. This study shows that FGF1, FGF2, FGFR1 and FGFR2 are produced by rat oviduct cells during pregnancy and the post-partum period, and reproductive physiology is regulated not only by hormonal mechanisms, but also by growth factors.     

Epidermal growth factor and epidermal growth factor receptor immunoreactivity in the endothelial cells of the uterine artery and its branches during different stages of the estrous cycle in the pig

The uterine artery and its branches are the most important vessels that supply the uterus with blood, nutrients and active substances. Epidermal growth factor (EGF) and its receptor (EGFR) are expressed in many tissues, including reproductive organs, and is involved in angiogenesis, embryo implantation and development as well as in proliferation and differentiation of various cells. The aim of our study was to determine EGF and EGFR immunoexpression in the uterine artery and its branches during the estrous cycle in the pig. The experiment was performed on cryostat sections of the uterine artery and its branches stained immunohistochemically by ABC method. Light microscopic observations revealed the phase-related immunoreactivity of EGF and EGFR in the endothelial cells of the uterine artery and its branches. The highest intensity of EGF and EGFR immunoreaction in endothelial cells of the uterine artery was observed in the follicular phase. A significant decrease in the intensity of EGF and EGFR immunoreactivity was found in the middle luteal phase. Similar results of the immunostaining were found with regard to EGFR. In the endothelium of the uterine arterial branches, a significant increase in the intensity of EGF and EGFR-immunoreactivity was observed in the middle luteal phase. A decrease in the intensity of EGF immunostaining was observed in the late luteal phase. The phase-related expression of EGF and EGFR in the endothelium of the uterine artery and its branches suggest the modulatory effect of EGF and its receptor on the uterine artery and the region supplying these vessels.