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.

scholarly journals Enzymic changes in rabbit and rat mammary gland during the lactation cycle

1969 ◽  
Vol 112 (3) ◽  
pp. 293-301 ◽  
Author(s):  
Bilquis Gul ◽  
R. Dils
Keyword(s):  
Mammary Gland ◽  
Malate Dehydrogenase ◽  
Isocitrate Dehydrogenase ◽  
Pyruvate Carboxylase ◽  
Acid Synthesis ◽  
Mitochondrial Fraction ◽  
Soluble Form ◽  
Supernatant Fraction ◽  
Rat Mammary Gland ◽  
Lactation Cycle

1. Activities of glucose 6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44), isocitrate dehydrogenase (EC 1.1.1.42), malate dehydrogenase (EC 1.1.1.37), malate dehydrogenase (decarboxylating) (EC 1.1.1.40), and pyruvate carboxylase (EC 6.4.1.1) were determined in subcellular fractions of mammary gland from rabbits during pregnancy, at different stages of lactation and during weaning. The results were compared with those obtained in similar experiments with rat mammary gland. 2. Three bases of expression of the activity of enzymes in the particle-free supernatant fraction of mammary gland were compared. During lactation, activity expressed per mg. of particle-free supernatant protein (uncorrected for milk protein) correlated well with that expressed per μg. of DNA phosphorus. The disadvantages of expressing activities per g. wet wt. are discussed. 3. The major differences between the two tissues were: (a) neither malate dehydrogenase (decarboxylating) nor a soluble form of pyruvate carboxylase could be detected in rabbit mammary gland at any stage of the lactation cycle; (b) isocitrate dehydrogenase increased in activity during lactation in rabbit mammary gland, but not in that of the rat. 4. Pyruvate carboxylase in the mitochondrial fraction of rabbit mammary gland, and in both the mitochondrial and the soluble fractions of rat mammary gland, did not change in activity during lactation. 5. For each tissue, the NADP-dependent dehydrogenases studied had a high activity at all stages of the lactation cycle compared with the rate of fatty acid synthesis at mid-lactation. The significance of these results is discussed with respect to the supply of NADPH via NADH.

scholarly journals Regulation of lipogenic capacity in lactating rats

1982 ◽  
Vol 208 (3) ◽  
pp. 611-618 ◽  
Author(s):  
M R Grigor ◽  
A Geursen ◽  
M J Sneyd ◽  
S M Warren
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Malic Enzyme ◽  
Fatty Acid Synthase ◽  
Specific Activity ◽  
Mammary Glands ◽  
Lipogenic Enzymes ◽  
Pregnancy And Lactation ◽  
Specific Activities

1. The rate of mammary-gland lipogenesis measured in vivo from 3H2O was suppressed after decreasing the milk demand by decreasing the number of pups from ten to two or three, as well as by giving diets containing lipid [Grigor & Warren (1980) Biochem. J. 188, 61-65]. 2. The specific activities of the lipogenic enzymes fatty acid synthase, glucose 6-phosphate dehydrogenase and ‘malic’ enzyme increased between 6- and 10-fold in the mammary gland and between 2- and 3-fold in the livers during the first 10 days of lactation. The increases in specific activity coupled with the doubling of liver mass which occurred during pregnancy and lactation resulted in considerable differences in total liver activities when compared with virgin animals. 3. Although consumption of a diet containing 20% peanut oil suppressed the activities of the three lipogenic enzymes in the livers, only the ‘malic’ enzyme was affected in the mammary glands. 4. In contrast, decreased milk demand did not affect the specific activities of any of the liver enzymes, whereas it resulted in suppression of all three lipogenic enzymes of the mammary glands. There was no effect on either the cytoplasmic malate dehydrogenase or the lactate dehydrogenase of the mammary gland. 5. In all the experiments performed, the activity of the fatty acid synthase correlated with the amount of material precipitated by the rabbit antibody raised against rat fatty acid synthase.

scholarly journals Rat mammary-gland fatty acid synthase. A simple purification procedure and stoicheiometry of CoA ester binding

1982 ◽  
Vol 203 (1) ◽  
pp. 45-50 ◽  
Author(s):  
P M Ahmad ◽  
D S Feltman ◽  
F Ahmad
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Specific Activity ◽  
Simple Procedure ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Performic Acid ◽  
Mammary Tissue ◽  
Rat Mammary Gland

A simple procedure was devised which allows purification of rat lactating-mammary-gland fatty acid synthase to a high degree of purity, with recoveries of activity exceeding 50%. Over 50 mg of enzyme was isolated from 60 g of mammary tissue. The specific activity of the purified enzyme was about 2.5 mumol of NADPH oxidized/min per mg of protein at 37 degrees. The enzyme appeared homogeneous by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and by immunodiffusion analysis. Each mol (Mr 480 000) of the enzyme bound 3 mol of acetyl and 3-4 mol of malonyl groups when the binding experiments were performed at 0 degrees for 30 s. The presence of NADPH did not influence the binding stoicheiometry for these acyl-CoA derivatives. Approx. 2 mol of taurine was found per mol of the performic acid-oxidized enzyme, suggesting that there were 2 mol of 4′-phosphopantetheine in the native enzyme. Rat mammary-gland fatty acid synthase required free CoA for activity.

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.

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 Immunochemical studies with soluble and mitochondrial pyruvate carboxylase activities from rat tissues

1970 ◽  
Vol 119 (4) ◽  
pp. 735-742 ◽  
Author(s):  
F. J. Ballard ◽  
R. W. Hanson ◽  
Lea Reshef
Keyword(s):  
Adipose Tissue ◽  
Mammary Gland ◽  
Brown Adipose Tissue ◽  
Rat Liver ◽  
White Adipose Tissue ◽  
Pyruvate Carboxylase ◽  
Specific Activity ◽  
Rat Liver Mitochondria ◽  
Rat Tissues ◽  
Brown Adipose

1. Pyruvate carboxylase (EC 6.4.1.1), purified from rat liver mitochondria to a specific activity of 14 units/mg, was used for the preparation of antibodies in rabbits. 2. Tissue distribution studies showed that pyruvate carboxylase was present in all rat tissues that were tested, with considerable activities both in gluconeogenic tissues such as liver and kidney and in tissues with high rates of lipogenesis such as white adipose tissue, brown adipose tissue, adrenal gland and lactating mammary gland. 3. Immunochemical titration experiments with the specific antibodies showed no differences between the inactivation of pyruvate carboxylase from mitochondrial or soluble fractions of liver, kidney, mammary gland, brown adipose tissue or white adipose tissue. 4. The antibodies were relatively less effective in reactions against pyruvate carboxylase from sheep liver than against the enzyme from rat tissues. 5. Pyruvate carboxylase antibodies did not inactivate either propionyl-CoA carboxylase or acetyl-CoA carboxylase from rat liver. 6. It is concluded that pyruvate carboxylase in lipogenic tissues is similar antigenically to the enzyme in gluconeogenic tissues and that the soluble activities of pyruvate carboxylase detected in many rat tissues do not represent discrete enzymes but are the result of mitochondrial damage during tissue homogenization.

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 The intracellular location of pyruvate carboxylase, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase in lactating rat mammary gland

1978 ◽  
Vol 171 (1) ◽  
pp. 273-275 ◽  
Author(s):  
D J Taylor ◽  
B Crabtree ◽  
G H Smith
Keyword(s):  
Mammary Gland ◽  
Pyruvate Carboxylase ◽  
Citrate Synthase ◽  
Extraction Technique ◽  
Intracellular Location ◽  
Rat Mammary Gland ◽  
Hydroxyacyl Coa Dehydrogenase

The intracellular location of pyruvate carboxylase (EC 6.4.1.1), citrate synthase (EC 4.1.3.7) and 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) in rat mammary gland was investigated by using a fractional-extraction technique. The results indicate a mitochondrial location for all three enzymes.

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