Electrical potentials and cell-to-cell dye movement in mouse mammary gland during lactation

1984 ◽  
Vol 247 (1) ◽  
pp. C20-C25 ◽  
Author(s):  
S. E. Berga
Keyword(s):  
Mammary Gland ◽  
Lucifer Yellow ◽  
Mammary Epithelium ◽  
Mouse Mammary Gland ◽  
Dye Transfer ◽  
Alveolar Cells ◽  
Electrical Potentials ◽  
Lucifer Yellow Ch ◽  
Electrophysiological Studies

Stable potentials were recorded with microelectrodes in an in vivo preparation of the mammary gland from the anesthetized lactating mouse. Location of the microelectrode tip was determined by ionophoretic injection of the fluorescent dye Lucifer yellow CH. Fifteen dye injections were localized to mammary alveolar cells; the average recorded potential for these penetrations was -49 +/- 2 mV. Cell-to-cell dye transfer between alveolar cells was observed with all intracellular Lucifer yellow injections. Ten dye injections were localized to the alveolar lumina with an average recorded potential of -35 +/- 2 mV. With these penetrations Lucifer yellow spread rapidly to many alveolar lumina. These findings indicate that stable potentials can be obtained from both cells and lumina in the in vivo mammary gland, demonstrating the feasibility of electrophysiological studies of the mammary epithelium. The presence of a large transepithelial potential provides evidence for physiologically tight junctions between mammary alveolar cells. In addition, the distribution of Lucifer yellow shows that mammary alveolar cells are coupled and suggests that milk flows freely between alveolar lumina.

scholarly journals Activation of retinoblastoma protein in mammary gland leads to ductal growth suppression, precocious differentiation, and adenocarcinoma

2002 ◽  
Vol 156 (1) ◽  
pp. 185-198 ◽  
Author(s):  
Zhe Jiang ◽  
Eldad Zacksenhaus
Keyword(s):  
Cell Proliferation ◽  
Mammary Gland ◽  
Cellular Proliferation ◽  
Mammary Epithelium ◽  
Specific Effect ◽  
Mouse Mammary Gland ◽  
Transient Activation ◽  
Proliferation And Apoptosis

The retinoblastoma (Rb) tumor suppressor controls cellular proliferation, survival, and differentiation and is functionally inactivated by mutations or hyperphosphorylation in most human cancers. Although activation of endogenous Rb is thought to provide an effective approach to suppress cell proliferation, long-term inhibition of apoptosis by active Rb may have detrimental consequences in vivo. To directly test these paradigms, we targeted phosphorylation-resistant constitutively active Rb alleles, RbΔKs, to the mouse mammary gland. Pubescent transgenic females displayed reduced ductal elongation and cell proliferation at the endbuds. Postpuberty transgenic mice exhibited precocious cellular differentiation and β-casein expression and extended survival of the mammary epithelium with a moderate but specific effect on the expression of E2F1, IGF1Rα, and phospho–protein kinase B/AKT. Remarkably, ∼30% RbΔK transgenic females developed focal hyperplastic nodules, and ∼7% exhibited full-blown mammary adenocarcinomas within 15 mo. Expression of the RbΔK transgene in these mammary tumors was reduced greatly. Our results suggest that transient activation of Rb induces cancer by extending cell survival and that the dual effects of Rb on cell proliferation and apoptosis impose an inherent caveat to the use of the Rb pathway for long-term cancer therapy.

Progesterone and EGF inhibit mouse mammary gland prolactin receptor and beta-casein gene expression

1994 ◽  
Vol 267 (5) ◽  
pp. C1467-C1472 ◽  
Author(s):  
S. Nishikawa ◽  
R. C. Moore ◽  
N. Nonomura ◽  
T. Oka
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Prolactin Receptor ◽  
Mammary Epithelium ◽  
Mouse Mammary Gland ◽  
Mrna Levels ◽  
Casein Gene ◽  
Beta Casein

Regulation of mouse mammary gland long-form prolactin receptor (PRL-RL) mRNA levels by progesterone and epidermal growth factor (EGF) and the relationship between PRL-RL and beta-casein gene expression were examined in vivo and in vitro. PRL-RL and beta-casein mRNA levels increased approximately 6- and 15-fold from the pregnant to the lactating period, respectively, when normalized to the level of beta-actin mRNA. Ovariectomy of pregnant mice rapidly reduced the serum concentration of progesterone and increased the level of PRL-RL and beta-casein mRNAs approximately three- and fourfold compared with sham-operated animals 24 h after the operation. Injection of progesterone, but not estrogen, inhibited the increase in both mRNA levels. PRL-RL and beta-casein mRNA levels in cultured mammary epithelium increased in response to insulin, hydrocortisone, and prolactin, whereas progesterone or EGF caused inhibition. The combination of EGF and progesterone produced a greater inhibition than either hormone alone. These results indicate that both progesterone and EGF serve as negative regulators of lactogenesis.

scholarly journals Retroviral expression of Wnt-1 and Wnt-7b produces different effects in mouse mammary epithelium

2000 ◽  
Vol 113 (12) ◽  
pp. 2129-2138 ◽  
Author(s):  
S. Naylor ◽  
M.J. Smalley ◽  
D. Robertson ◽  
B.A. Gusterson ◽  
P.A. Edwards ◽  
...  
Keyword(s):  
Cell Culture ◽  
Mammary Gland ◽  
Mammary Gland Development ◽  
Ectopic Expression ◽  
Mammary Epithelium ◽  
Mouse Mammary Gland ◽  
Normal Mammary Gland ◽  
Gland Development

Several Wnt genes are expressed in the postnatal mouse mammary gland and are thought to be involved in mammary gland development. Ectopic expression of Wnt-1, which is not normally expressed in the mammary gland, drives the formation of a pre-neoplastic hyperplasia. Cell culture-based assays have shown that Wnt-1 and some mammary-expressed Wnts transform C57MG cells. This has led to the suggestion that Wnt-1 functions as an oncogene through the inappropriate activation of developmental events that are normally controlled by the ‘transforming’ class of Wnts. In this study, Wnt-7b was expressed in vivo using recombinant retroviruses. Wnt-7b did not alter normal mammary gland development despite having similar effects to Wnt-1 in cell culture. We conclude that the in vitro classification of Wnts as ‘transforming’ does not correlate with the transformation in vivo. To facilitate the analysis of Wnt-expression, a lacZ-containing, bicistronic recombinant retrovirus was developed. Immunohistochemistry and electron microscopy identified retrovirally transduced myoepithelial and luminal epithelial cells in normal and hyperplastic tissues. The distribution of transduced cells in mammary outgrowths was consistent with current models of mammary stem cell identity.

scholarly journals In vivo MRI of early stage mammary cancers and the normal mouse mammary gland

2011 ◽  
Vol 24 (7) ◽  
pp. 880-887 ◽  
Author(s):  
Sanaz A. Jansen ◽  
Suzanne D. Conzen ◽  
Xiaobing Fan ◽  
Erica Markiewicz ◽  
Thomas Krausz ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Normal Mouse ◽  
Early Stage ◽  
Mouse Mammary Gland

scholarly journals Fine-tuning of Epithelial EGFR signals Supports Coordinated Mammary Gland Development

2020 ◽  
Author(s):  
Alexandr Samocha ◽  
Hanna M. Doh ◽  
Vaishnavi Sitarama ◽  
Quy H. Nguyen ◽  
Oghenekevwe Gbenedio ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelium ◽  
Gene Signature ◽  
Mammary Epithelial ◽  
Fine Tuning ◽  
Basal Cells ◽  
Stem And Progenitor Cells

SummaryDuring puberty, robust morphogenesis occurs in the mammary gland; stem- and progenitor-cells develop into mature basal- and luminal-cells to form the ductal tree. The receptor signals that govern this process in mammary epithelial cells (MECs) are incompletely understood. The EGFR has been implicated and here we focused on EGFR’s downstream pathway component Rasgrp1. We find that Rasgrp1 dampens EGF-triggered signals in MECs. Biochemically and in vitro, Rasgrp1 perturbation results in increased EGFR-Ras-PI3K-AKT and mTORC1-S6 kinase signals, increased EGF-induced proliferation, and aberrant branching-capacity in 3D cultures. However, in vivo, Rasgrp1 perturbation results in delayed ductal tree maturation with shortened branches and reduced cellularity. Rasgrp1-deficient MEC organoids revealed lower frequencies of basal cells, the compartment that incorporates stem cells. Molecularly, EGF effectively counteracts Wnt signal-driven stem cell gene signature in organoids. Collectively, these studies demonstrate the need for fine-tuning of EGFR signals to properly instruct mammary epithelium during puberty.

RAPIDLY-LABELLED RNA IN THE MOUSE MAMMARY GLAND BEFORE AND DURING LACTATION

1973 ◽  
Vol 56 (1) ◽  
pp. 145-152 ◽  
Author(s):  
D. N. BANERJEE ◽  
M. R. BANERJEE
Keyword(s):  
Mammary Gland ◽  
Ribosomal Rna ◽  
Gradient Analysis ◽  
Sucrose Density Gradient ◽  
Mouse Mammary Gland ◽  
Nuclear Fraction ◽  
Cytoplasmic Rna ◽  
Nuclear Rna ◽  
Nuclear Synthesis

SUMMARY Linear sucrose density gradient analysis showed that the synthesis of rapidly-labelled high molecular weight RNA was virtually absent in the mammary glands of virgin mice. The rapidly-labelled RNA was first evident in the mammary gland in pregnancy and was also present during lactation. The bulk of this newly-made nuclear RNA sedimented as 45S and 32S fractions after a 15-min [3H]uridine pulse period in vivo. No labelled 18S RNA was detectable in the nuclear fraction after the 15-min pulse but it was present in the cytoplasm, suggesting that the 18S RNA migrates to the cytoplasm almost immediately after its formation. Thirty minutes after injection of [3H]uridine, the initial radioactivity of the 45S region migrated to the 32S fraction and a labelled 28S peak was also present in the cytoplasmic RNA at 60 min, suggesting that the processed 28S ribosomal RNA in the mammary gland began to migrate to the cytoplasm between 30 and 60 min after the nuclear synthesis of the precursor molecule.

scholarly journals Development of mouse mammary gland: identification of stages in differentiation of luminal and myoepithelial cells using monoclonal antibodies and polyvalent antiserum against keratin.

1986 ◽  
Vol 34 (8) ◽  
pp. 1037-1046 ◽  
Author(s):  
A Sonnenberg ◽  
H Daams ◽  
M A Van der Valk ◽  
J Hilkens ◽  
J Hilgers
Keyword(s):  
Monoclonal Antibodies ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Cell Types ◽  
Mouse Mammary Gland ◽  
Type I ◽  
Basal Cells ◽  
Alveolar Cells ◽  
Luminal Type

The development of the mouse mammary gland was studied immunohistochemically using monoclonal antibodies against cell surface and basement membrane proteins and a polyclonal antibody against keratin. We have identified three basic cell types: basal, myoepithelial, and epithelial cells. The epithelial cells can be subdivided into three immunologically related cell types: luminal type I, luminal type II, and alveolar cells. These five cell types appear at different stages of mammary gland development and have either acquired or lost one of the antibody-defined antigens. The cytoplasmic distribution of several of these antigens varied according to the location of the cells within the mammary gland. Epithelial cells which did not line the lumen expressed antigens throughout the cytoplasm. These antigens were demonstrated on the apical site in situations where the cells lined the lumen. One antigen became increasingly basolateral as the cells became attached to the basement membrane. The basal cells synthesize laminin and deposit it at the cell base. They are present in endbuds and ducts and are probably the stem cells of the mammary gland. Transitional forms have been demonstrated which developmentally link these cells with both myoepithelial and (luminal) epithelial cells.

scholarly journals The p53 tumor suppressor gene is regulated in vivo by nuclear factor 1-C2 in the mouse mammary gland during pregnancy

Oncogene ◽  
2003 ◽  
Vol 22 (38) ◽  
pp. 6061-6070 ◽  
Author(s):  
Eva M Johansson ◽  
Marie Kannius-Janson ◽  
Gunnar Bjursell ◽  
Jeanette Nilsson
Keyword(s):  
Mammary Gland ◽  
Tumor Suppressor ◽  
Tumor Suppressor Gene ◽  
Suppressor Gene ◽  
Mouse Mammary Gland ◽  
Nuclear Factor ◽  
P53 Tumor Suppressor ◽  
P53 Tumor Suppressor Gene ◽  
Nuclear Factor 1

scholarly journals The effect of lipid derivative of anti-tumor drug sarcolysin embedded in phospholipid nanoparticles in the experiments in vivo

2021 ◽  
Vol 67 (6) ◽  
pp. 491-499
Author(s):  
Yu.A. Tereshkina ◽  
T.I. Torkhovskaya ◽  
M.A. Sanzhakov ◽  
L.V. Kostryukova ◽  
Yu.Yu. Khudoklinova ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Antitumor Agent ◽  
Mouse Mammary Gland ◽  
Lymphocytic Leukemia ◽  
Pharmacokinetic Parameters ◽  
Tumor Growth Inhibition ◽  
Phospholipid Nanoparticles ◽  
Lipid Derivative ◽  
Ld50 Value

To improve the therapeutic properties of the antitumor agent Sarcolysin, we have previously developed and characterized a dosage form representing its ester conjugate with decanol embedded in ultra-small phospholipid nanoparticles less than 30 nm in size (“Sarcolysin-NP”). The effect of the resulting composition was investigated in vivo in comparison with the free substance of sarcolysin. The composition intravenous administration to mice showed an improvement in the pharmacokinetic parameters of sarcolysin associated with its initial higher (by 22%) level in the blood and prolonged circulation, which was also observed in mice with P388 tumor. In mice with three types of tumors — lymphocytic leukemia P388, lymphocytic leukemia L1210, and adenocarcinoma of the mammary gland Ca755 — administration of two doses of sarcolysin over a period of 7 days showed its predominant antitumor effect. The maximum tumor growth inhibition was noted for lymphocytic leukemia L1210 and adenocarcinoma of the mouse mammary gland Ca755 (at a dose of Sarcolysin-NP — 8,4 mg/kg), which was higher in comparison with free substance by more than 24% and 17%, respectively. Differences in the life span of the treated animals were revealed significantly at a dose of 10 mg/kg and amounted to 25% and 17,4% for lymphocytic leukemia P388 and L1210, respectively, and 11% for adenocarcinoma Ca755. In an experiment on rats, acute toxicity of Sarcolysin-NP administered intravenously showed that an average LD50 value 2-3 times exceeded a similar parameter for commercial preparations of free sarcolysin (Melphalan and Alkeran), which indicates its lower toxicity.

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