scholarly journals Studies on the particulate components of rat mammary gland. 2. Changes in the levels of the nucleic acids of the mammary glands of rats during pregnancy, lactation and mammary involution

1957 ◽  
Vol 66 (1) ◽  
pp. 155-161 ◽  
Author(s):  
A. L. Greenbaum ◽  
T. F. Slater
Keyword(s):  
Mammary Gland ◽  
Nucleic Acids ◽  
Mammary Glands ◽  
Mammary Involution ◽  
Rat Mammary Gland

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.

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.

scholarly journals Lysosomal enzyme changes in enforced mammary-gland involution

1965 ◽  
Vol 97 (2) ◽  
pp. 518-522 ◽  
Author(s):  
AL Greenbaum ◽  
TF Slater ◽  
DY Wang
Keyword(s):  
Mammary Gland ◽  
Rapid Decrease ◽  
Mammary Involution ◽  
Mammary Gland Involution ◽  
Reserpine Treatment ◽  
Histological Appearance ◽  
Antihistamine Drug ◽  
Rat Mammary Gland ◽  
Early Phases ◽  
Enzyme Changes

1. Changes occurring in the activities and latency of acid ribonuclease and beta-glucuronidase have been studied in rat mammary gland during the early phases of mammary involution. 2. It was found that there were rapid increases in the proportions of both enzymes in the; free' (i.e. unsedimentable) form. The total activities of both enzymes did not show the rapid decrease characteristic of most other enzymes studied during mammary-gland involution. 3. The effects of pretreating the rats with reserpine or the antihistamine drug Phenergan on these lysosomal changes was studied. Neither treatment affected the enzymic redistribution that occurs during early involution. 4. It was concluded that lysosomal rupture occurs as an early manifestation of mammary-gland involution. Although reserpine treatment preserves the histological appearance of the gland and, apparently, inhibits involution, this drug did not prevent the lysosomal changes normally found in suspensions.

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 Lactogenesis in the rat. Changes in metabolic parameters at parturition

1967 ◽  
Vol 105 (3) ◽  
pp. 995-1002 ◽  
Author(s):  
N. J. Kuhn ◽  
J. M. Lowenstein
Keyword(s):  
Mammary Gland ◽  
Nucleic Acids ◽  
Biosynthetic Pathway ◽  
Metabolic Parameters ◽  
Tissue Concentrations ◽  
Rat Mammary Gland

1. Tissue concentrations of nucleic acids, protein, fat, water, metabolites and lactose, and the activities of seven enzymes concerned in milk biosynthesis, were measured in the rat mammary gland at closely spaced times before, at and after parturition. 2. Changes are seen in the tissue concentrations of most substances, and several changes are initiated at least during the day preceding parturition. 3. Lactose, which is absent 1 day before parturition, is found in amounts of 12μmoles/g. fresh wt. of tissue at parturition. 4. From the tissue activities before parturition of three enzymes on the biosynthetic pathway of lactose, and, from the small changes observed in their activities at parturition itself, it is concluded that the factors responsible for the appearance of lactose at parturition remain to be demonstrated.

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.

PHOSPHORUS METABOLISM IN VIRAL-INDUCED NEOPLASIA: II. IN VIVO AND IN VITRO STUDIES OF THE MILK AND MAMMARY GLAND LIPIDES OF STRAINS OF MICE SUSCEPTIBLE TO THE MAMMARY TUMOR VIRUS

1965 ◽  
Vol 43 (3) ◽  
pp. 297-307 ◽  
Author(s):  
James Newland ◽  
R. F. McGregor ◽  
W. E. Cornatzer
Keyword(s):  
Fatty Acid Composition ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Nucleic Acids ◽  
Acid Composition ◽  
Mammary Tumor ◽  
Mammary Glands ◽  
Phosphorus Metabolism ◽  
Mammary Tumor Virus ◽  
Tumor Virus

Studies of phosphorus metabolism in the mammary glands of C3HZ, C3HZb, and A strain female mice have been carried out using P32-labeled inorganic phosphate. Chemical and radioactivity measurements of labeled phospholipides, nucleic acids, and phosphoproteins of mammary tissue were obtained. The fatty acid composition of the chromatographed and separated phospholipides, neutral fat, and free fatty acids of milk of high-cancer-strain (C3HZ and A) females were compared to patterns obtained for low-cancer-strain (C3HZb) females. The lipide pattern of the mammary tumor virus fraction obtained by ultra-centrifugation was investigated and compared to the results found for mammary gland and milk. The C3HZ female bearing mammary tumors exhibited increased synthesis of phospholipides and nucleic acids when compared to the genetically similar, low-cancer-strain C3HZb females and to identical C3HZ females that had not yet developed mammary tumors. Investigation of the phospholipide fatty acid composition of the milk and mammary glands of high- and low-cancer strains revealed further marked differences with respect to the palmitoleic and linoleic acid content.

scholarly journals Hyperthyroidism and production of precocious involution in the mammary glands of lactating rats

Reproduction ◽  
2002 ◽  
pp. 691-702 ◽  
Author(s):  
SM Varas ◽  
EM Munoz ◽  
MB Hapon ◽  
CI Aguilera Merlo ◽  
MS Gimenez ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Binding Sites ◽  
Mammary Glands ◽  
Insulin Like Growth Factor ◽  
Mammary Involution ◽  
Igf I ◽  
Mammary Gland Epithelial Cells

This study investigated the influence of chronic hyperthyroidism on mammary function in lactating rats and the effects on their pups. Thyroxine-treated (10 microg per 100 g body weight per day; hyperthyroid (HT)) or vehicle-treated rats were mated 2 weeks after the start of treatment and killed with their litters on days 7, 14 and 21 of lactation. Serum concentrations of triiodothyronine (T(3)) and tetraiodothyronine (T(4)) increased in thyroxine-treated rats. In HT mothers, serum prolactin decreased on day 7 and day 14 of lactation, whereas insulin-like growth factor I (IGF-I) and progesterone concentrations decreased, and corticosterone increased on day 7 of lactation. In HT pups, T(4) concentration increased on day 7 and day 14 of lactation, whereas T(3) increased only on day 14 of lactation, and growth hormone increased on day 7 of lactation. Mammary prolactin binding sites did not vary, but there was an increase in the binding sites in the liver on day 14 of lactation in thyroxine-treated rats. In an acute suckling experiment, thyroxine-treated rats released less oxytocin, growth hormone and prolactin and excreted less milk than did control rats. Mammary casein, lactose and total lipid concentrations in thyroxine-treated rats were similar to those of control rats on day 14 of lactation. Histological studies of the mammary glands showed an increased proportion of alveoli showing reduced or no lumina and cells with condensed nuclei on day 14 and day 21 of lactation; the TdT-mediated dUTP nick-end labelling (TUNEL) test revealed an increase in apoptosis in alveolar cells on day 21 of lactation in thyroxine-treated rats. Expression of SGP-2, a gene expressed during mammary involution, increased in thyroxine-treated rats on day 14 and day 21 of lactation, whereas expression of insulin-like growth factor binding protein 5, a proapoptotic signal, was unchanged. Bcl-2, which promotes survival of mammary gland epithelial cells was unchanged, whereas expression of IGF-I, which also promotes survival of mammary gland epithelial cells, increased on day 21 of lactation in thyroxine-treated rats. These results indicate that thyroxine treatment produces some milk stasis as a result of impairments in suckling induced release of oxytocin that may initiate the first stage of mammary involution, increasing apoptosis in a gland that is otherwise actively producing and secreting milk.

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