• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.585-592
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• 2004

Our previous studies demonstrated that relaxin in concert with estrogen promotes development of the mammary parenchyma during the last third of gestation in gilts, and the specific relaxin-binding sites were present in the mammary gland. This study was conducted to determine if relaxin-binding sites in the mammary gland were functional relaxin receptors. Three cycling cross-bred gilts were bilaterally ovariectomized on day 0 of the experiment. Beginning on day 15 and continuing through day 29 post-surgery, the gilt received an im. injection of estradiol benzoate at 12-hr intervals. Beginning on day 22 post-surgery, highly purified porcine relaxin was administered(lug/hr) into the left fourth mammary gland from the anterior end via miniature osmotic pump. Physiological saline was administered to the right fourth mammary gland. The gilt was sacrificed on day 29 post-surgery and histological characteristics of the mammary parenchyma were examined. The mammary glands treated locally with saline showed little, if any, lobulo-alveolar development, whereas the mammary glands treated with relaxin showed not only marked lobulo-alveolar development but also prominent secretions in the alveoli. The saline-treated glands were characterized by relatively dense and highly organized collagen fiber bundles. Whereas, in the relaxin-treated mammary glands, collagen fiber bundles were dispersed and loosely organized. In conclusion, relaxin-binding sites in the mammary gland are functional relaxin receptors and relaxin acts directly on the pig mammary gland to promote development of the alveoli and remodeling of the extracellular matrix.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.1
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• pp.43-46
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• 1988

Based on our previous results that among 4 strains of mice SHN and GR/A showed the highest mammary growth potentials in females and males, respectively. Effects of crossbreeding on normal and neoplastic mammary growth were studied in $(SHN\;{\times}\;GR/A)F_1$ virgin female mice. $F_1$ mice were higher than the parental strains in the end-bud formation and the ductal growth of mammary glands at 60 days of age and at tumorous age, respectively. While there was little difference between $F_1$ and both parental strains in the onset age of the first mammary tumors, mammary tumorigenic potential was apparently higher in the former than in the latters. This would be the first report that demonstrated directly the contribution of mammary growth potential of males to that of female offspring.

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.133-139
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• 1994

Two human lactoferrin expression vectors(pCChcLf and pCChcLf-1) were constructed using rat $\beta$-casein gene and human lactoferrin cDNA. The recombinant DNAs containing human lactoferrin cDNA were microinjected into the fertilized eggs of hybrid mice (BDF1 : C57BL$\times$DBA) and the DNA-injected eggs were treansferred into the oviducts of foster mothers. Genomic DNAs were isolated from the tails of mice born from the microinjected eggs and analyzed by Southern blot analysis. As a result, 5 and 9 transgenic mice with CChcLf and CChcLf-1 gene were produced, respectively. To determine tissue-specificity of transgene expression, Northern blot analysis was performed. Female transgenic mice were killed at day 10 of lactation and total RNAs from various tissues were isolated. Based on Northern blot analysis, it was shown that transgene was mainly expressed in the mammary glands of transgenic mice. In addition, the human lactoferrin in milk was detected by enzyme-linked immunosorbent assay. For this study, milk was obtained from the mammary glands of the transgenic mice at day 10 of lactation. In line #2 of CChcLf and line #7 of CChcLf-1 transgenic mice, human lactoferrin was secreted into the milk at concentration levels of 340ng/ml and 60ng/ml, respectively.

• Korean Journal of Veterinary Research
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• v.47 no.1
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• pp.1-6
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• 2007

The importance of milk for the growth and health of a newborn offspring is well known. Milkcontains immunoglobulin G (Ig G), Ig A, lactoperoxidase, lactoferin, cytokines, and growth factors.Osteopontin, one of the multifunctional proteins, is secreted by macrophages, T cel, and epithelial cells.bovine milk have not been clarified. The aim of this study was to observe the expression of osteopontin,in bovine milk during the lactation period or bovine mamary glands..Western blot analysis detected thatosteopontin was expressed in bovine milk whey and mamary glands. The expression level of osteopontinin colostrum whey was higher than those in early milk and mature milk whey. Immunohistochemistryshowed that osteopontin was detected in the glandular epithelium and epithelial cels of intralobular ductof mamary glands. These findings suggest that osteopontin transiently shows high expression in colostrumand plays a potential role in the immunological development of breast-fed calves.

• Archives of Pharmacal Research
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• v.28 no.3
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• pp.351-357
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• 2005

Endosulfan is one of the organochlorine pesticides, which are well-known endocrine disruptors (EDs), and it acts as an estrogen agonist. Estrogen is a group of hormones that play an important role in mammary gland function and are implicated in mammary carcinogenesis. In the present study, we studied the effects of endosulfan on nodule like alveolar lesion (NLAL) formation in mouse mammary gland development using a mouse mammary gland organ culture (MMOC) system. Although endosulfan-treated mammary glands did not form NLALs, more alveolar buds were formed in this group than in the negative control (vehicle-treated) group. In addition, telomerase reverse transcriptase (TERT) mRNA expression levels were increased in endosulfan-treated mammary glands in a dose-dependent manner. Telomerase can be activated by estrogen, therefore, we examined the effects of endosulfan on telomerase activity, and found that the telomerase activity in estrogen receptor-positive MCF-7 cells was up-regulated by endosulfan treatment. Moreover, this activation was accompanied by the up­regulation of the TERT mRNA expression. Also, transient expression assays using CAT reporter plasm ids containing various fragments of the TERT promoter showed that this imperfect palindromic estrogen-responsive element is almost certainly responsible for the transcriptional activation by endosulfan. These results may help elucidate the endocrine disrupting mechanism of endosulfan.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.3
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• pp.139-142
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• 1988

Effects of anthranilic acid on normal mammary gland growth were examined in SHN/Mei female virgin mice. Anthranilic acid was given to the experimental groups as drinking water at the concentrations of 0.01, 0.02 or 0.04% for 21 days beginning 2-3 months of age. The control group received tap water only. RNA content and RNA/DNA ratio in mammary glands were significantly higher in mice given 0.04% anthranilic acid than in the control, while not mammary DNA content. The results indicate that chronic ingestion of anthranilic acid can induce an enhancement of proliferation and differentiation of mammary cells.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.59-59
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• 2001

Interleukin-10 (IL-10) is known as a regulator of inflammation and pathogenesis in mammalian organs, but its precise role is little known in the mammary gland. Our initial experiment showed that IL-10 expression levels in mice decreased at the lactation stage otherwise increased at the involution stage. To reveal the effects of IL-10 on the involution of mammary gland, expression profiles of the apoptosis-related genes were examined in transgenic mice expressing human IL-10 as well as in knock-out mice (IL-10-/-). Mild inflammatory legions by lymphocytes were observed in the mammary glands of transgenic lines at the lactation stage. The expression of TRAIL (Tumor necrosis factor-Related Apoptosis-Inducing Ligand) among the apoptosis-related genes was highly elevated in the transgenic mice while others were not significantly changed. Furthermore, TRAIL was down regulated by four fold in the IL-10-/- mice at the involution stage. The expression of DR4 was elevated at the involution stage of normal mice. DR4 was detected in the milk of transgenic mice but absent in that of normal mice. Our results proposed that the elevated IL-10 at the involution stage recruit lymphocytes and induce TRAIL and DR4 genes, therefore, lead to enter involution stage of mammary glands.

• Korean Journal of Veterinary Research
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• v.56 no.4
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• pp.229-232
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• 2016

Mammary gland tumors are very rare in male dogs. In this study, four mammary gland tumors from 3 male dogs (2 intact, 1 neutered) were collected from local animal hospitals. The dogs included two purebred Shih Tzu (1 intact, 1 neutered) and one intact purebred Cocker Spaniel. The mean age of dogs with mammary gland tumors was 9 years (5-12 years). Two dogs had a solitary mass, whereas one dog had two mammary masses. Of the four tumor masses, three were observed in the fourth or fifth mammary glands, and one was observed in the third mammary gland. According to histopathologic examinations, all four mammary masses from three dogs were benign tumors including two benign mixed tumors in one case and two complex adenomas. There were no history of obesity, testicular tumors, diabetes, and sex hormonal therapy in any male dogs with mammary tumors. Surgical excision was the only reported treatment for these tumors. No recurrence or metastasis was recorded up to 25 months after surgery.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.12
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• pp.1774-1783
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• 2015

Milk lysozyme is the ubiquitous enzyme in milk of mammals. In this study, the cDNA sequence of a new chicken-type (c-type) milk lysozyme gene (YML), was cloned from yak mammary gland tissue. A 444 bp open reading frames, which encodes 148 amino acids (16.54 kDa) with a signal peptide of 18 amino acids, was sequenced. Further analysis indicated that the nucleic acid and amino acid sequences identities between yak and cow milk lysozyme were 89.04% and 80.41%, respectively. Recombinant yak milk lysozyme (rYML) was produced by Escherichia coli BL21 and Pichia pastoris X33. The highest lysozyme activity was detected for heterologous protein rYML5 (M = 1,864.24 U/mg, SD = 25.75) which was expressed in P. pastoris with expression vector $pPICZ{\alpha}A$ and it clearly inhibited growth of Staphylococcus aureus. Result of the YML gene expression using quantitative polymerase chain reaction showed that the YML gene was up-regulated to maximum at 30 day postpartum, that is, comparatively high YML can be found in initial milk production. The phylogenetic tree indicated that the amino acid sequence was similar to cow kidney lysozyme, which implied that the YML may have diverged from a different ancestor gene such as cow mammary glands. In our study, we suggest that YML be a new c-type lysozyme expressed in yak mammary glands that plays a role as host immunity.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.198.2-199
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• 2000