scholarly journals Enhanced synthesis of gelatinase and stromelysin by myoepithelial cells during involution of the rat mammary gland.

1992 ◽  
Vol 40 (5) ◽  
pp. 697-703 ◽  
Author(s):  
S R Dickson ◽  
M J Warburton
Keyword(s):  
Mammary Gland ◽  
Basement Membrane ◽  
Gelatin Zymography ◽  
Mammary Glands ◽  
Myoepithelial Cells ◽  
Immunofluorescence Staining ◽  
Rat Mammary Gland

During the involution of the mammary gland there is destruction of the basement membrane as the secretory alveolar structures degenerate. Immunofluorescence staining of sections of rat mammary gland with antibodies to 72 KD gelatinase (MMP-2) and stromelysin (MMP-3) revealed increased production of these two proteinases during involution. This increased expression was mostly restricted to myoepithelial cells. Increased expression during involution was also demonstrated by immunoblotting techniques. Gelatin zymography indicated that the predominant metalloproteinase present in involuting rat mammary glands was a 66 KD gelatinase.

scholarly journals Distribution of myoepithelial cells and basement membrane proteins in the resting, pregnant, lactating, and involuting rat mammary gland.

1982 ◽  
Vol 30 (7) ◽  
pp. 667-676 ◽  
Author(s):  
M J Warburton ◽  
D Mitchell ◽  
E J Ormerod ◽  
P Rudland
Keyword(s):  
Mammary Gland ◽  
Membrane Proteins ◽  
Epithelial Cells ◽  
Connective Tissue ◽  
Basement Membrane ◽  
Myoepithelial Cells ◽  
Type I ◽  
Continuous Layer ◽  
Basement Membrane Proteins ◽  
Rat Mammary Gland

Using antisera to specific proteins, the localization of the rat mammary parenchymal cells (both epithelial and myoepithelial), the basement membrane, and connective tissue components has been studied during the four physiological stages of the adult rat mammary gland, viz. resting, pregnant, lactating, and involuting glands. Antisera to myosin and prekeratin were used to localize myoepithelial cells, antisera to rat milk fat globule membrane for epithelial cells, antisera to laminin and type IV collagen to delineate the basement membrane and antisera to type I collagen and fibronectin as markers for connective tissue. In the resting, virgin mammary gland, myoepithelial cells appear to form a continuous layer around the epithelial cells and are in turn surrounded by a continuous basement membrane. Antiserum to fibronectin does not delineate the basement membrane in the resting gland. The ductal system is surrounded by connective tissue. Only the basal or myoepithelial cells in the terminal end buds of neonatal animals demonstrate cytoplasmic staining for basement membrane proteins, indicating active synthesis of these proteins during this period. In the secretory alveoli of the lactating rat, the myoepithelial cells no longer appear to form a continuous layer beneath the epithelial cells and in many areas the epithelial cells appear to be in contact with the basement membrane. The basement membrane in the lactating gland is still continuous around the ducts and alveoli. In the lactating gland, fibronectin appears to be located in the basement membrane region in addition to being a component of the stroma. During involution, the alveoli collapse, and appear to be in a state of dissolution. The basement membrane is thicker and is occasionally incomplete, as also are the basket-like myoepithelial structures. Basement membrane components can also be demonstrated throughout the collapsed alveoli.

EFFECT OF LOCALLY IMPLANTED OESTROGEN ON THE RESPONSE OF THE RAT'S LACTATING MAMMARY GLAND TO OXYTOCIN

1973 ◽  
Vol 73 (4) ◽  
pp. 700-712 ◽  
Author(s):  
J. D. Bruce ◽  
X. Cofre ◽  
V. D. Ramirez
Keyword(s):  
Mammary Gland ◽  
Mammary Glands ◽  
Myoepithelial Cells ◽  
Recording System ◽  
Saline Infusion ◽  
High Dose ◽  
Low Doses ◽  
Milk Ejection ◽  
Lactating Mammary Gland ◽  
Small Rise

ABSTRACT On the day following delivery (day 1 of lactation) one abdominal mammary gland was implanted with oestrogen and the contralateral gland received an empty needle. At 2, 5 or 10 days of lactation the rats were anaesthetized with pentobarbital and the nipples of both abdominal glands were cannulated and their pressures recorded by means of transducers coupled to an amplifier and recording system. The normal mammary glands of 5-day lactating rats responded to very low doses of oxytocin (Syntocinon®, Sandoz) (5× 10−8 mU) with a rhythmic elevation in pressure. However, saline infusion also evoked a small rise in intra-mammary pressure. Earlier (2 days) and later (10 days) in lactation the responses were smaller. Oestrogen decreases significantly the milk ejection response to oxytocin, and the effect was maximal at day 10 of lactation. Histological observations confirmed the diminished reaction of the gland to oxytocin, since the milk was retained in the alveoli of rats bearing a mammary-oestrogen implant. A paradoxical rise in pressure was detected in normal as well as in oestrogen-implanted glands when the lowest dose of oxytocin was injected in lactating rats which had previously received a high dose of oxytocin (50 mU or 500 mU). These results reinforce the hypothesis that oestrogen alters the milk ejection response to oxytocin and that the mechanism is probably related to changes in the contractility of the myoepithelial cells.

Mammary gland cell content during various phases of lactation

1962 ◽  
Vol 203 (5) ◽  
pp. 939-941 ◽  
Author(s):  
Richard C. Moon
Keyword(s):  
Mammary Gland ◽  
Deoxyribonucleic Acid ◽  
Cellular Proliferation ◽  
Gland Cell ◽  
Late Pregnancy ◽  
Mammary Glands ◽  
Lactation Period ◽  
Cell Content ◽  
Rat Mammary Gland ◽  
Mammary Gland Cell

Deoxyribonucleic acid (DNA) was used as an index of the cellular state of the rat mammary gland in late pregnancy ( day 20) and early ( day 1), intense ( day 14), and declining ( day 28) lactation. Dams sacrificed on day 28 of lactation were provided with foster litters on day 14 postpartum to insure a strong sucking stimulus during the lactation period from days 14–28. Mammary DNA increased 57% from day 20 of pregnancy to lactation day 14, but no significant change in DNA content was evident by day 1 of lactation. A significantly lower DNA concentration was observed in mammary glands of rats sacrificed at lactation day 28 when compared with that of animals killed at day 14 of lactation. The data suggest that cellular proliferation of mammary gland continues well into lactation and that a decline in lactation may be due, in part, to a reduction in the number of milk-secreting cells.

Amyloid in the Corpora Amylacea of the Rat Mammary Gland

1978 ◽  
Vol 15 (3) ◽  
pp. 347-352 ◽  
Author(s):  
R. B. Beems ◽  
E. Gruys ◽  
B. J. Spit
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Mammary Gland ◽  
Amyloid Fibrils ◽  
Mammary Glands ◽  
Amyloid Deposition ◽  
Corpora Amylacea ◽  
Rat Mammary Gland

Histochemical and electron microscope studies indicated there was amyloid in corpora amylacea in tumors, duct ectasias and lobular hyperplasias of rat mammary glands. Electron microscopy showed fibrils that closely resembled amyloid fibrils in human and bovine amyloid and in bovine corpora amylacea. Amyloid deposition may be more common in rats than is generally thought.

scholarly journals Prolactin receptor expression in the epithelia and stroma of the rat mammary gland

2001 ◽  
Vol 171 (1) ◽  
pp. 85-95 ◽  
Author(s):  
IG Camarillo ◽  
G Thordarson ◽  
JG Moffat ◽  
KM Van Horn ◽  
N Binart ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Mammary Glands ◽  
Receptor Expression ◽  
Mrna Levels ◽  
Western Blots ◽  
Stromal Compartment ◽  
Mouse Tissues ◽  
Epithelial Compartment ◽  
Rat Mammary Gland ◽  
Mammary Tissues

The importance of prolactin (PRL) in regulating growth and differentiation of the mammary gland is well known. However, it is not well established whether PRL acts solely on the mammary epithelia or if it can also directly affect the mammary stroma. To determine where PRL could exert its effects within the mammary gland, we investigated the levels of expression and the localization of the PRL receptor (PRLR) in the epithelia and stroma of the rat mammary gland at different physiological stages. For these studies, we isolated parenchymal-free 'cleared' fat pads and intact mammary glands from virgin, 18-day-pregnant and 6-day-lactating rats. In addition, intact mammary tissues were enzymatically digested to obtain epithelial cells, free of stroma. The mammary tissues, intact gland, stroma and isolated epithelia, were then used for immunocytochemistry, protein extraction and isolation of total RNA. PRLR protein was detected in tissues using specific polyclonal antisera (PRLR-l) by immunocytochemistry and Western blot analysis. Messenger RNA for PRLR was measured by ribonuclease protection assay. Immunocytochemistry and Western blots with the PRLR-1 antisera detected PRLR in wild-type rat and mouse tissues, whereas the receptor protein was absent in tissues from PRLR gene-deficient mice. PRLR was found to be present both in the epithelia and stroma of mammary glands from virgin, pregnant and lactating rats, as determined by immunocytochemistry and Western blotting. Western blots revealed the predominance of three bands migrating at 88, 90 and 92 kDa in each of the rat mammary samples. These represent the long form of the PRLR. During pregnancy and lactation, PRLR protein increased in the epithelial compartment of the mammary gland but did not change within the stromal compartment at any physiological stage examined. We also found PRLR mRNA in both the epithelia and stroma of the mammary gland. Again, the stroma contained lower levels of PRLR mRNA compared with the epithelia at all physiological stages examined. Also, the PRLR mRNA levels within the stroma did not change significantly during pregnancy or lactation, whereas PRLR mRNA within the epithelia increased twofold during pregnancy and fourfold during lactation when compared with virgin rats. We conclude from this study that PRLR is expressed both in the stromal and epithelial compartment of the mammary gland. This finding suggests PRL may have a direct affect on the mammary stroma and by that route affect mammary gland development.

scholarly journals Pyruvate carboxylase in lactating rat and rabbit mammary gland

1969 ◽  
Vol 111 (3) ◽  
pp. 263-271 ◽  
Author(s):  
Bilquis Gul ◽  
R. Dils
Keyword(s):  
Mammary Gland ◽  
Pyruvate Carboxylase ◽  
Freeze Drying ◽  
Specific Activity ◽  
Subcellular Fractionation ◽  
Mammary Glands ◽  
Mitochondrial Fraction ◽  
Freezing And Thawing ◽  
Rat Mammary Gland ◽  
Assay Conditions

1. Pyruvate carboxylase [pyruvate–carbon dioxide ligase (ADP), EC 6.4.1.1] was found in cell-free preparations of lactating rat and rabbit mammary glands, and optimum assay conditions for this enzyme were determined. 2. Subcellular-fractionation studies with marker enzymes showed pyruvate carboxylase to be distributed between the mitochondrial and soluble fractions of lactating rat mammary gland. Evidence is presented that the soluble enzyme is not an artifact due to mitochondrial damage. 3. In contrast, pyruvate carboxylase in lactating rabbit mammary gland is confined to the mitochondrial fraction. 4. The final product of pyruvate carboxylase action in the mitochondrial and particle-free supernatant fractions of lactating rat mammary gland was shown to be citrate. 5. The effects of freeze-drying, ultrasonic treatment and freezing-and-thawing on the specific activity of mitochondrial pyruvate carboxylase were investigated.

Distribution of entactin in the basement membrane of the rat mammary gland

1984 ◽  
Vol 152 (1) ◽  
pp. 240-254 ◽  
Author(s):  
Michael J. Warburton ◽  
Paul Monaghan ◽  
Sharon A. Ferns ◽  
Philip S. Rudland ◽  
Nina Perusinghe ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Basement Membrane ◽  
Rat Mammary Gland

scholarly journals Expression of Bone Morphogenetic Protein-6 (BMP-6) in Myoepithelial Cells in Canine Mammary Gland Tumors

2001 ◽  
Vol 38 (6) ◽  
pp. 703-709 ◽  
Author(s):  
S. Tateyama ◽  
K. Uchida ◽  
T. Hidaka ◽  
M. Hirao ◽  
R. Yamaguchi
Keyword(s):  
Mammary Gland ◽  
Basement Membrane ◽  
Bone Morphogenetic Protein ◽  
Mammary Tumors ◽  
Myoepithelial Cells ◽  
Cytokeratin 19 ◽  
Mammary Gland Tumors ◽  
Morphogenetic Protein ◽  
Canine Mammary Gland ◽  
Mixed Tumors

Seventy-three mammary tumors and three mammary tissue specimens were examined to elucidate the expression of bone morphogenetic protein (BMP)-6 in the myoepithelial cells of canine mammary gland tumors. Morphologically, the myoepithelial cells were classified into four types: resting and proliferating cells inside the basement membrane, and spindle- and star-shaped cells proliferating in the outer area of the basement membrane. The characteristics of these myoepithelial cells were confirmed by immunohistochemistry using antibodies raised against keratin, cytokeratin 19, alpha-smooth muscle actin, and vimentin. In simple adenoma, a small number of resting myoepithelial cells was immunopositive for BMP-6. In complex adenomas and benign mixed tumors, all types of myoepithelial cells, depending in some cases on their specific location within the tumor, were immunopositive for BMP-6, but almost all of the tubular epithelial cells were immunonegative. Foci consisting of a proliferation of BMP-6–positive star- and spindle-shaped cells had mucinous stroma with marked hyaline and chondroid changes. In contrast, the foci with BMP-6–negative spindle- and star-shaped cells tended to have mucinous stroma without chondroid change. Several types of mesenchymal cells including chondrocytes, osteoblasts, and fibroblastlike cells in the mixed tumors, showed an intense immunopositive reaction for the BMP-6 antibody, and were located close to the ectopic cartilage and bone matrix. No significant immunoreactivity for BMP-6 was observed in most of the malignant mammary tumors; only one malignant mixed tumor was examined. All of these findings indicate that BMP-6 expression in myoepithelial cells may increase in complex adenomas and benign mixed tumors in canine mammary glands, and that BMP-6 expression is most intense in the vicinity of chondroid matrix in these tumors.

A new monoclonal antibody to a cell-surface antigen that distinguishes luminal epithelial and myoepithelial cells in the rat mammary gland

1989 ◽  
Vol 94 (3) ◽  
pp. 545-552
Author(s):  
R.S. Mahendran ◽  
M.J. O'Hare ◽  
M.G. Ormerod ◽  
P.A. Edwards ◽  
R.A. McIlhinney ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Milk Fat ◽  
Single Cells ◽  
Myoepithelial Cells ◽  
Stages Of Development ◽  
Leukaemia Cell Line ◽  
Flow Cytometric ◽  
Rat Mammary Gland

A monoclonal antibody (25.5) has been produced that recognises luminal epithelial cells of the rat mammary gland. This antibody together with monoclonal anti-CALLA antibodies, which react with mammary myoepithelial cells, has been used in biochemical, immunocytochemical and flow cytometric studies. Antibody 25.5 bound to proteins of molecular weight 70K and 25K (K = 10(3) Mr) in both the rat milk fat globule membrane and in single cell suspensions prepared from the virgin adult rat mammary gland. Anti-CALLA antibody (J5), recognised a 93–100K protein in the gland extracts, which co-electrophoresed with the CALLA/CD-10 antigen from NALM-6 acute lymphoblastic leukaemia cell line. Antibody 25.5 bound to the luminal surface of rat mammary epithelial cells at all stages of development from neonatal through to pregnancy, lactation and involution. CALLA immunoreactive staining has previously been shown on basally located presumptive myoepithelial cells at all stages of development. Flow cytometric analyses demonstrated that 25.5 and anti-CALLA antibodies stained independent cell populations in suspensions of single cells prepared from purified epithelial elements from the mammary gland of adult virgin rat.

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