A HISTOLOGICAL AND FUNCTIONAL STUDY OF THE MAMMARY GLAND IN NORMAL AND AGALACTIC SOWS

1958 ◽  
Vol 17 (1) ◽  
pp. 63-NP ◽  
Author(s):  
B. A. CROSS ◽  
R. F. W. GOODWIN ◽  
I. A. SILVER
Keyword(s):  
Alkaline Phosphatase ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Dose Response ◽  
Myoepithelial Cells ◽  
Functional Study ◽  
Milk Ejection ◽  
Histological Changes ◽  
Alveolar Structure ◽  
Clinical Cases

SUMMARY 1. A method has been devised for obtaining repeated biopsy samples from the mammaryglands of sows, and by its use the histological changes associated with farrowing have been studied. 2. Before farrowing, the alveoli were at first small and filled with a hyaline eosinophilic secretion. Progressive distension of the alveoli followed, accompanied by a gradual replacement of the eosinophilic material by basophilic secretion and the onset of fat secretion. At farrowing the alveoli were contracted and their contents evacuated. 3. Acute involutional changes seen in the engorged glands of early-weaned animals, or animals that were suckled with one teat occluded, were characterized by solidification of the alveoli, swollen degenerating epithelial cells and, later, stromal proliferation. Little alveolar structure remained after 8 days. 4. Descriptions are given of three main types of mammary defect that were detected histologically in clinical cases of agalactia. 5. In experiments on milk ejection, recorded manometrically, the dose-response relation to injected oxytocin was determined. Two out of three sows responded to 10 mu. and maximal responses were obtained with doses of 200–500 mu. 6. The occurrence of myoepithelial cells in the sow's mammary gland has been demonstrated by the alkaline phosphatase technique.

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.

Oxytocin receptors in rat involuting mammary gland

1983 ◽  
Vol 61 (7) ◽  
pp. 631-635 ◽  
Author(s):  
Melvyn S. Soloff ◽  
Michael H. Wieder
Keyword(s):  
Alkaline Phosphatase ◽  
Mammary Gland ◽  
Fold Increase ◽  
Myoepithelial Cells ◽  
Oxytocin Receptor ◽  
Secretory Cells ◽  
Specific Marker ◽  
Oxytocin Receptors ◽  
Pregnancy And Lactation ◽  
Receptor Number

Oxytocin-receptor concentrations in the rat mammary gland were determined by Scatchard analyses with [3H]oxytocin. There was about a 100-fold increase in the number of receptors per mammary gland between the 1st day of pregnancy and late lactation. The number of receptors then fell markedly during postweaning mammary regression, but rose again during a second pregnancy and lactation cycle. The changes in oxytocin-receptor number corresponded to changes in alkaline phosphatase activity per mammary gland. These results strongly support data suggesting that alkaline phosphatase, like oxytocin receptors, is a specific marker for mammary myoepithelial cells. Despite the fall in oxytocin-receptor number per mammary gland during postweaning regression, the concentration of receptors, expressed per milligram of protein, increased 10-fold over lactating levels on the 6th day of regression. Thereafter, receptor concentrations declined, but were still elevated about fivefold over lactating levels on the 15th day of regression. It is likely that the increased concentration of receptors was due to a decrease in the relative amount of nontarget secretory cells. The factors that regulate the concentration of oxytocin receptors on mammary myoepithelial cells are presently unknown; however, the involuting mammary system may be practical for obtaining enriched populations of oxytocin-sensitive myoepithelial cells.

Complex mammary tumours in the female dog: a review

2005 ◽  
Vol 72 (S1) ◽  
pp. 90-97 ◽  
Author(s):  
Eva Hellmén
Keyword(s):  
Mammary Gland ◽  
Growth Factors ◽  
Epithelial Cells ◽  
Sex Hormones ◽  
Myoepithelial Cells ◽  
The Body ◽  
Pronounced Effect ◽  
Mammary Tumours ◽  
Luminal Epithelial Cells

Spontaneous mammary tumours are most frequently seen (apart from rodents) in women, female dogs and cats. The mammary gland is the most commonly affected organ for tumours in women and in female dogs. The mammary gland has a similar histology in the different species whereas the number of glands differs as well as the number of interlobular ducts that reach the nipple/teat. The parenchymatous tissue is composed of alveoli that turn into interlobular ducts. The whole ductal tree is outlined by a two-layered epithelium with the luminal epithelial cells adjacent to the lumen and the more sparse myoepithelial cells peripherally located to these. Different proteins such as growth factors regulate the mammary gland, as they do for all tissues in the body. In addition, sex hormones regulate the biology of the mammary gland. Oestrogen has the most pronounced effect on duct growth whereas progesterone promotes growth of the alveoli.

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.

scholarly journals Mex3c mutation affects lactation through impairing milk ejection in female mice

2020 ◽  
Vol 40 (12) ◽  
Author(s):  
Yong Du ◽  
Dongjun Sun ◽  
Yan Li
Keyword(s):  
Mammary Gland ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mammary Glands ◽  
Myoepithelial Cells ◽  
Mutant Mice ◽  
Milk Ejection ◽  
Female Mice ◽  
Antiviral Innate Immunity ◽  
Gland Development

Abstract Mouse Mex3c encodes RNA-binding proteins of variant length through alternative splicing. Its mutation results in multiple defects including growth retardation, perturbed energy balance, and defective antiviral innate immunity. Here we report that Mex3c mutation affects mammary gland development and lactation in female mice. Pups of Mex3c mutant dams die of starvation soon after birth. Milk contents are present in the alveoli but deficient in the ducts of the mammary glands in mutant mice. Mutant mice do not show prolactin or oxytocin deficiency. They also develop myoepithelial cells in the mammary glands. Mex3c is expressed in the mammary gland epithelium. Our data suggest that functional defects in mammary gland epithelium or myoepithelial cells could cause lactation defects.

scholarly journals Expression of Maspin in Mammary Gland Tumors of the Dog

2005 ◽  
Vol 42 (3) ◽  
pp. 250-257 ◽  
Author(s):  
A. Espinosa de los Monteros ◽  
M. Y. Millán ◽  
G. A. Ramírez ◽  
J. Ordás ◽  
C. Reymundo ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Malignant Tumors ◽  
Myoepithelial Cells ◽  
Benign Tumors ◽  
Normal Mammary Gland ◽  
Differentiation Markers ◽  
Maspin Expression ◽  
Cellular Compartments

Maspin is a serine protease inhibitor that inhibits tumor invasion and metastasis in human breast cancer and is consistently expressed by mammary myoepithelial cells (MECs). To analyze the value of maspin as a marker of the MEC layer of the normal and tumoral canine mammary gland, the immunohistochemical expression of maspin was studied in formalin-fixed tissues from 55 benign and malignant tumors (40 tumors also contained the surrounding normal mammary gland) using a commercially available monoclonal antibody. Periacinar and periductal MECs of all 40 normal mammary glands were stained by the anti-human maspin monoclonal antibody, and immunoreactivity was observed in the nucleus and cytoplasm of these cells. In addition, maspin was found in 53 (98%) of the tumors studied, reacting with the MECs in 100% of benign tumors and 93% of malignant tumors and to the epithelial cells of 16% of benign and 73% of malignant tumors. In the MEC compartment, immunoreactivity was observed in the cytoplasm of hypertrophic MECs, fusiform MECs, stellate MECs, rounded (myoepithelial) cells, and chondroblasts. In the epithelial cell compartment, immunoreactivity was observed in the cytoplasm of cells with and without squamous differentiation. Stromal myofibroblasts were unreactive. Maspin appears to be a very sensitive marker of the normal and neoplastic myoepithelium that, contrary to smooth muscle differentiation markers, does not stain stromal myofibroblasts. In addition, a subset of neoplastic epithelial cells reacted with the maspin antibody. The relationship between maspin expression in different cellular compartments of canine mammary carcinomas and the biologic aggressiveness of the disease remains to be elucidated.

scholarly journals Dispersed mammary gland epithelial cells. I. Isolation and separation procedures.

1977 ◽  
Vol 72 (2) ◽  
pp. 390-405 ◽  
Author(s):  
J P Kraehenbuhl
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Connective Tissue ◽  
Structural Integrity ◽  
Plasma Cells ◽  
Buoyant Density ◽  
Light And Electron Microscopy ◽  
Enzymatic Digestion ◽  
Myoepithelial Cells ◽  
Tissue Cells

The mammary gland from midpregnant rabbits has been dissociated into individual cells by enzymatic digestion, divalent cation chelation, and gentle shearing. A heterogeneous cell population is obtained, comprising approximately 60% parenchymal cells, approximately 10% myoepithelial cells, and approximately 30% connective tissue cells, including fibroblasts, plasma cells, and microphages. The epithelial cells are characterized by the presence of fat droplets, which in 65% of the cells form large supranuclear vacuoles. Their buoyant density is less than 1.045, allowing their separation from myoepithelial cells and connective tissue cells by isopycnic centrifugation in a density gradient. The homogeneity of the epithelial cell fraction has been assessed by light and electron microscopy. The cells are viable and functionally active as indicated by their ability to exclude vital dyes, incorporate labeled precursors, consume oxygen, maintain intracellular Na+ and K+ concentrations, and retain their structural integrity. In addition, when cultured in Petri dishes, the cells grow as a monolayer, reestablish junctional complexes and retain cell polarity.

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.

scholarly journals Mammary gland adipocytes in lactation cycle, obesity and breast cancer

2021 ◽  
Author(s):  
Georgia Colleluori ◽  
Jessica Perugini ◽  
Giorgio Barbatelli ◽  
Saverio Cinti
Keyword(s):  
Breast Cancer ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Close Association ◽  
Critical Role ◽  
Exocrine Gland ◽  
Plastic Properties ◽  
Lactation Cycle ◽  
Gland Development

AbstractThe mammary gland (MG) is an exocrine gland present in female mammals responsible for the production and secretion of milk during the process of lactation. It is mainly composed by epithelial cells and adipocytes. Among the features that make the MG unique there are 1) its highly plastic properties displayed during pregnancy, lactation and involution (all steps belonging to the lactation cycle) and 2) its requirement to grow in close association with adipocytes which are absolutely necessary to ensure MG’s proper development at puberty and remodeling during the lactation cycle. Although MG adipocytes play such a critical role for the gland development, most of the studies have focused on its epithelial component only, leaving the role of the neighboring adipocytes largely unexplored. In this review we aim to describe evidences regarding MG’s adipocytes role and properties in physiologic conditions (gland development and lactation cycle), obesity and breast cancer, emphasizing the existing gaps in the literature which deserve further investigation.

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