Compensatory nutrition-directed mammary cell proliferation and lactation in rats

The proper use of a time-dependent and controlled nutrition regimen during the hormone-sensitive growth phase before first parturition can significantly affect mammary growth and subsequent lactation performance. The objective of the present study was to determine if a compensatory nutrition regimen improves lactation performance by affecting proliferation and apoptosis of mammary epithelial cells. Forty female rats (7 weeks of age, average weight 148 g) were assigned to either (1) control, free access to diet or (2) stair-step compensatory nutrition regimen, an alternating 3–4-week schedule beginning with an energy-restricted diet (31·2% restriction) for 3 weeks, followed by the control diet for 4 weeks. Estimated milk yield was greater (P <0·05) on day 15 of lactation in the compensatory nutrition group than in the control group. Mammary cell proliferation values were 1·4- and 2·7-fold greater in mammary tissue from the compensatory group during pregnant and early lactating stages respectively, compared with those from the control group. Ornithine decarboxylase (EC 4.1.1.17)mRNA was 24% higher (P <0·05) in mammary tissues of rats from the compensatory nutrition group during pregnancy than in those from the control group. These results indicate that the compensatory nutrition regimen imposed during the peripubertal growth phase stimulated mammary epithelial cell proliferation and improved lactation performance.

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Milk examination

International Journal of Veterinary Science and Research ◽

10.17352/ijvsr.s1.109 ◽

2018 ◽

pp. 062-064

Author(s):

Tagesu Abdisa

Keyword(s):

Cell Proliferation ◽

Milk Production ◽

Mammary Epithelial Cells ◽

Mammary Epithelium ◽

Secretory Activity ◽

Mammary Epithelial ◽

Lactation Performance ◽

Production Potential ◽

Structural Differentiation ◽

Mammary Cell

Milk production potential is a function of the number of mammary epithelial cells in the, gland, as well as the secretory activity of those cells [1,2]. Therefore, improved lactation performance can be achieved under conditions that enhance mammary cell proliferation (or decrease apoptosis), biochemical and structural differentiation of mammary epithelium, and synthesis and secretion of milk components [1].

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Effects of exercise on insulin distribution and action in testosterone-treated oophorectomized female rats

Journal of Applied Physiology ◽

10.1152/jappl.2000.88.6.2116 ◽

2000 ◽

Vol 88 (6) ◽

pp. 2116-2122 ◽

Cited By ~ 9

Author(s):

Maria Niklasson ◽

Peter Daneryd ◽

Peter Lönnroth ◽

Agneta Holmäng

Keyword(s):

Insulin Resistance ◽

Physical Exercise ◽

Insulin Action ◽

Female Rats ◽

Control Group ◽

Free Access ◽

Euglycemic Hyperinsulinemic Clamp ◽

Severe Insulin Resistance ◽

Ovx Rats ◽

Running Wheels

Administration of testosterone (T) to oophorectomized (Ovx) female rats is followed by severe insulin resistance, localized to postreceptor cellular events in the muscle. In this study, intervention by exercise was introduced to examine whether circulatory adaptations are involved in insulin resistance. Two groups of Ovx rats were studied: one group was given T (Ovx+T); another group had free access to running wheels (Ovx+T+Ex). In addition, one control group (sham operated) was studied. Insulin sensitivity was measured with the euglycemic hyperinsulinemic clamp technique (submaximal) for 150 min. Muscle interstitial glucose and insulin concentrations were measured by microdialysis. The measurements showed that, in Ovx+T rats, the onset of insulin action was significantly ( P < 0.05) slower during the first 95 min of the clamp compared with that in Ovx+T+Ex and controls. Muscle interstitial concentrations of insulin but not glucose were lower in both Ovx+T and Ovx+T+Ex rats than in controls throughout the clamp. It was concluded that physical exercise prevented the slow onset of insulin action in Ovx+T rats without changing the distribution time of muscle interstitial insulin. The results indicate that hyperandrogenicity is characterized by delayed muscle insulin action. Physical exercise reverses these defects without any beneficial effect on muscle interstitial insulin concentrations.

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Impaired Glucose Metabolism in Young Offspring of Female Rats with Hypothyroidism

Journal of Diabetes Research ◽

10.1155/2019/4713906 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Zhoujun Liu ◽

Yu Chen ◽

Guofang Chen ◽

Xiaodong Mao ◽

Xiao Wei ◽

...

Keyword(s):

Cell Proliferation ◽

Glucose Metabolism ◽

Tap Water ◽

Mrna Level ◽

Young Male ◽

Female Rats ◽

Control Group ◽

Pancreatic Cell ◽

Insulin Synthesis ◽

Young Offspring

Purpose. Because thyroid hormones from the maternal thyroid glands are known to influence the growth, development, and metabolic functioning of offspring, we used a rat model to preliminarily investigate the effects of maternal hypothyroidism on glucose metabolism, pancreas cell proliferation, and insulin production in young male offspring and the possible underlying mechanisms. Methods. Female rats were divided into a maternal hypothyroidism (MH) group, which received water containing 0.02% 6-propyl-2-thiouracil before and during pregnancy to induce hypothyroidism, and a control group which consumed tap water. Results. Our results showed that there were no differences of islets structure between the offspring from the two groups, but glucose metabolism was impaired with higher plasma glucose concentrations at 0 and 15 min in the OGTT in 8-week-old offspring of the MH group. From birth to 8 weeks, pancreatic TRβ1 and TRβ2 mRNA level declined significantly in MH offspring, accompanied by decreased Ki67 and insulin mRNA expression. Conclusions. Maternal hypothyroidism results in impaired pancreatic insulin synthesis and pancreatic cell proliferation in neonatal offspring and subsequent glucose intolerance in young offspring, which may be related to TRβ gene downregulation in the pancreas.

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Use of Chlorella as a carrier of organic-bound iodine in the nutrition of sows

Czech Journal of Animal Science ◽

10.17221/4267-cjas ◽

2011 ◽

Vol 49 (No. 1) ◽

pp. 28-32 ◽

Cited By ~ 6

Author(s):

V. Kotrbáček ◽

J. Doucha ◽

T. Offenbartl

Keyword(s):

Iodine Concentration ◽

Feed Consumption ◽

Iodine Uptake ◽

Control Group ◽

Average Weight ◽

Lactation Period ◽

Lactation Performance ◽

Total Iodine ◽

Weight Gains ◽

On Farm

The effect of supplementation with iodine incorporated into biomass of the unicellular alga Chlorella on the content of this element in colostrum and milk was investigated in sows of the Large White breed. Experiments were conducted in two elite herds with different levels of iodine supply in basal feed mixtures. On farm A the feed mixture contained 1 549 µg I/kg, on farm B it was 228 µg I/kg. Pregnant sows on both farms were divided into control and experimental group a fortnight before parturition. Control group comprised 8 sows on farm A and 6 sows on farm B. As the sows on both farms received feed rations of 3 kg feed per head/day, iodine uptake of control animals was 4 647 µg I per head/day on farm A and 684 µg I per head/day on farm B. In addition to this supply experimental sows, 9 animals on farm A and 6 animals on farm B, received 450 µg per head/day of iodine bound in Chlorella biomass. Total iodine uptake was 5 097 µg per head/day on farm A and 1 134 µg per head/day on farm B. Supplementation also continued in the lactation period when total iodine uptake increased with increasing feed consumption. The supplement of organically bound iodine for experimental sows continued to be 450 µg per head/day. Colostrum samples were taken in both groups on the first two days after parturition while milk samples were taken at the end of the third week of lactation. Iodine concentration in these samples and in feed mixtures was determined spectrophotometrically according to Sandell-Kolthoff’s method. Numbers of born and reared piglets, and lactation performance of sows determined by weighing litters on day 21 of piglet life were investigated in individual sows. This litter weight was used to calculate average weight gains of piglets for the period of investigations. The supplementation of Chlorella -bound iodine increased the content of this element in colostrum of experimental sows from 365 ± 81 µg/l to 492 ± 122 µg/l on farm A (p < 0.05) and from 241 ± 70 µg/l to 391 ± 75 µg/l on farm B (p < 0.01). Iodine concentration in milk decreased in all sows, particularly in the animals included in both experimental groups, where it decreased to about half the values detected in colostrum (p < 0.01). Lower iodine content in milk of supplemented sows corresponded with their higher lactation performance. Differences in milk production were obvious mainly on farm B, i.e. in sows with low uptake of dietary iodine. The average lactation performance of supplemented sows on this farm was 61.2 ± 7.95 kg/head while in controls it was 54.9 ± 4.22 kg/head. As the number of experimental animals was low, this difference was below the level of statistical significance. Neither was it possible to prove the higher weight gains of piglets found out in both experimental groups on a significance level. No relationship was established between the number of reared piglets and supplementation of organically bound iodine. It can be concluded from the results that the supplementation of iodine bound in Chlorella biomass increased its concentration in colostrum of sows with both the low and the high dietary uptake of this element, which proved its good utilisation. A possible positive effect of this supplementation on lactation performance of sows and weight gains of piglets should be verified in further experiments.  

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CYTOCHROME OXIDASE AND SUCCINIC OXIDASE ACTIVITY IN MAMMARY GLAND MITOCHONDRIA OF LACTATING RATS

Canadian Journal of Biochemistry and Physiology ◽

10.1139/y55-111 ◽

1955 ◽

Vol 33 (1) ◽

pp. 904-908

Author(s):

Jules Tuba ◽

Patricia F. Orr ◽

G. Stuart Wiberg

Keyword(s):

Mammary Gland ◽

Cytochrome Oxidase ◽

Oxidase Activity ◽

Succinic Dehydrogenase ◽

Female Rats ◽

Oxidative Enzymes ◽

Mammary Tissue ◽

Control Group ◽

Succinic Dehydrogenase Activity ◽

Rat Mammary Gland

The effect of lactation on some oxidative enzymes of rat mammary gland mitochondria was examined. Cytochrome oxidase levels were nearly doubled during lactation. Succinic oxidase activity was not demonstrable in breeder female rats four days after the cessation of nursing, or in a control group (non-lactating breeder females, which had weaned their young at least four weeks previously), but during the nursing period considerable activity of the enzyme was observed. Succinic dehydrogenase activity was negligible in mitochondria during involution of rat mammary tissue. On the other hand appreciable anaerobic glycolysis occurred in the resting gland. The greatly increased metabolic activity associated with lactation is reflected in the altered behavior of some of the enzymes of rat mammary gland mitochondria.

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RagD regulates amino acid mediated-casein synthesis and cell proliferation via mTOR signalling in cow mammary epithelial cells

Journal of Dairy Research ◽

10.1017/s0022029918000146 ◽

2018 ◽

Vol 85 (2) ◽

pp. 204-211 ◽

Cited By ~ 2

Author(s):

Ying Mu ◽

Dongmei Zheng ◽

Cong Wang ◽

Wei Yu ◽

Xiaonan Zhang

Keyword(s):

Cell Proliferation ◽

Amino Acid ◽

Epithelial Cells ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Mammary Tissue ◽

Lactation Period ◽

Mtor Inhibition ◽

Pregnancy And Lactation ◽

Casein Synthesis

This research paper addresses the hypothesis that RagD is a key signalling factor that regulates amino acid (AA) mediated-casein synthesis and cell proliferation in cow mammary epithelial cells (CMECs). The expression of RagD was analysed at different times during pregnancy and lactation in bovine mammary tissue from dairy cows. We showed that expression of RagD at lactation period was higher (P < 0·05) than that at pregnancy period. When CMECs were treated with methionine (Met) or lysine (Lys), expression of RagD, β-casein (CSN2), mTOR and p-mTOR, and cell proliferation were increased. Further, when CMECs were treated to overexpress RagD, expression of CSN2, mTOR and p-mTOR, and cell proliferation were up-regulated. Furthermore, the increase in expression of CSN2, mTOR and p-mTOR, and cell proliferation in response to Met or Lys supply was inhibited by inhibiting RagD, and those effects were reversed in the overexpression model. When CMECs were treated with RagD overexpression together with mTOR inhibition or conversely with RagD inhibition together with mTOR overexpression, results showed that the increase in expression of CSN2 and cell proliferation in response to RagD overexpression was prevented by inhibiting mTOR, and those effects were reversed by overexpressing mTOR. The interaction of RagD with subunit proteins of mTORC1 was analysed, and the result showed that RagD interacted with Raptor. CMECs were treated with Raptor inhibition, and the result showed that the increase in expression of mTOR and p-mTOR in response to RagD overexpression was inhibited by inhibiting Raptor.In conclusion, our study showed that RagD is an important activation factor of mTORC1 in CMECs, activating AA-mediated casein synthesis and cell proliferation, potentially acting via Raptor.

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Unilateral once daily milking locally induces differential gene expression in both mammary tissue and milk epithelial cells revealing mammary remodeling

Physiological Genomics ◽

10.1152/physiolgenomics.00059.2013 ◽

2013 ◽

Vol 45 (20) ◽

pp. 973-985 ◽

Cited By ~ 22

Author(s):

Marion Boutinaud ◽

Laurent Galio ◽

Vanessa Lollivier ◽

Laurence Finot ◽

Sandra Wiart ◽

...

Keyword(s):

Gene Expression ◽

Cell Proliferation ◽

Epithelial Cells ◽

Immunomagnetic Separation ◽

Local Effect ◽

Mammary Epithelial ◽

Oligonucleotide Array ◽

Cell Subpopulation ◽

Mammary Tissue ◽

Once Daily

Once daily milking reduces milk yield, but the underlying mechanisms are not yet fully understood. Local regulation due to milk stasis in the tissue may contribute to this effect, but such mechanisms have not yet been fully described. To challenge this hypothesis, one udder half of six Holstein dairy cows was milked once a day (ODM), and the other twice a day (TDM). On the 8th day of unilateral ODM, mammary epithelial cells (MEC) were purified from the milk using immunomagnetic separation. Mammary biopsies were harvested from both udder halves. The differences in transcript profiles between biopsies from ODM and TDM udder halves were analyzed by a 22k bovine oligonucleotide array, revealing 490 transcripts that were differentially expressed. The principal category of upregulated transcripts concerned mechanisms involved in cell proliferation and death. We further confirmed remodeling of the mammary tissue by immunohistochemistry, which showed less cell proliferation and more apoptosis in ODM udder halves. Gene expression analyzed by RT-qPCR in MEC purified from milk and mammary biopsies showed a common downregulation of six transcripts ( ABCG2, FABP3, NUCB2, RNASE1 and 5, and SLC34A2) but also some discrepancies. First, none of the upregulated transcripts in biopsies varied in milk-purified MEC. Second, only milk-purified MEC showed significant LALBA downregulation, which suggests therefore that they correspond to a mammary epithelial cell subpopulation. Our results, obtained after unilateral milking, suggest that cell remodeling during ODM is due to a local effect, which may be triggered by milk accumulation.

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Antidiabetic effect of 2-(4- [(2-hydroxyacetyl benzyl) ketoamino]-phenyl amino-methyl)- hydrobenzophenon on Alloxan induced rats

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v11i4.3930 ◽

2020 ◽

Vol 11 (4) ◽

pp. 7425-7428

Author(s):

Vurimi Bhopal Chandra ◽

Kudagi B L ◽

Madhavulu Buchineni ◽

Pathapati Rama Mohan ◽

Anjani Devi Nelavala

Keyword(s):

Diabetes Mellitus ◽

Blood Sugar ◽

Antidiabetic Activity ◽

Control Group ◽

Albino Rats ◽

Average Weight ◽

Free Access ◽

High Blood Glucose ◽

Sugar Levels ◽

Wistar Albino Rats

Diabetes Mellitus is known as a syndrome, a collection of disorders with high blood glucose level & glucose intolerance as its feature, either because of insulin deficiency or insulin impairment or both. Diabetes Mellitus, based on insulin, is broadly classified into two types. Type one indicates the distraction of pancreatic β - cells that leads to diabetes mellitus, in which insulin is necessary to prevent ketoacidosis, coma, death. Type two diabetes is characterized by disorders of insulin resistance & secretion. Male Wistar albino rats with an average weight of 180-250 g were used in this study. With a 12 hours’ light and dark period, they were kept under normal conditions (room temperature 24-27oC and humidity 60-65 %). The free access of drinking water & pellet diet to male Wistar albino rats was allowed, as per the CPCSEA guidelines. Anti-diabetic activity of Compound 2-(4- [(2-hydroxyacetyl benzyl) ketoamino]-phenyl amino-methyl)- hydrobenzophenon, male Wistar albino rats were divided into four different groups. 1ml of blood samples were collected directly into anticoagulant bottles from the tail vein & later plasma was collected after centrifugation. Blood sugar levels were determined by spectrophotometer. There was a significant decrease in blood sugar levels in Alloxan + Glibenclamide and Alloxan + Compound groups on compared to control. The present self-funded study concludes that antidiabetic activity of 2-(4- [(2-hydroxyacetyl benzyl) ketoamino]-phenyl amino-methyl)- hydrobenzophenon in Alloxan induced diabetic rats significantly shows decreed blood sugar levels when compared to the control group.

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CYTOCHROME OXIDASE AND SUCCINIC OXIDASE ACTIVITY IN MAMMARY GLAND MITOCHONDRIA OF LACTATING RATS

Canadian Journal of Biochemistry and Physiology ◽

10.1139/o55-111 ◽

1955 ◽

Vol 33 (6) ◽

pp. 904-908 ◽

Cited By ~ 3

Author(s):

Jules Tuba ◽

Patricia F. Orr ◽

G. Stuart Wiberg

Keyword(s):

Mammary Gland ◽

Cytochrome Oxidase ◽

Oxidase Activity ◽

Succinic Dehydrogenase ◽

Female Rats ◽

Oxidative Enzymes ◽

Mammary Tissue ◽

Control Group ◽

Succinic Dehydrogenase Activity ◽

Rat Mammary Gland

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Effect of Heat Stress on Bovine Mammary Cellular Metabolites and Gene Transcription Related to Amino Acid Metabolism, Amino Acid Transportation and Mammalian Target of Rapamycin (mTOR) Signaling

Animals ◽

10.3390/ani11113153 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3153

Author(s):

Lin Fu ◽

Li Zhang ◽

Li Liu ◽

Heng Yang ◽

Peng Zhou ◽

...

Keyword(s):

Amino Acid ◽

Mrna Expression ◽

Signaling Pathway ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Mammary Epithelial ◽

Mtor Signaling ◽

Control Group ◽

Mtor Signaling Pathway ◽

Lactation Performance

Heat stress (HS) is one of the most serious factors to negatively affect the lactation performance of dairy cows. Bovine mammary epithelial cells are important for lactation. It was demonstrated that HS decreases the lactation performance of dairy cows, partly through altering gene expression within bovine mammary epithelial tissue. However, the cellular metabolism mechanisms under HS remains largely unknown. The objective of this study was to determine whether HS induced changes in intracellular metabolites and gene transcription related to amino acid metabolism, amino acid transportation and the mTOR signaling pathway. Immortalized bovine mammary epithelial cell lines (MAC-T cells, n = 5 replicates/treatment) were incubated for 12 h at 37 °C (Control group) and 42 °C (HS group). Relative to the control group, HS led to a greater mRNA expression of heat shock protein genes HSF1, HSPB8, HSPA5, HSP90AB1 and HSPA1A. Compared with the control group, metabolomics using liquid chromatography tandem–mass spectrometry identified 417 differential metabolites with p < 0.05 and a variable importance in projection (VIP) score >1.0 in the HS group. HS resulted in significant changes to the intracellular amino acid metabolism of glutathione, phenylalanine, tyrosine, tryptophan, valine, leucine, isoleucine, arginine, proline, cysteine, methionine, alanine, aspartate and glutamate. HS led to a greater mRNA expression of the amino acid transporter genes SLC43A1, SLC38A9, SLC36A1, and SLC3A2 but a lower mRNA expression of SLC7A5 and SLC38A2. Additionally, HS influenced the expression of genes associated with the mTOR signaling pathway and significantly upregulated the mRNA expression of mTOR, AKT, RHEB, eIF4E and eEF2K but decreased the mRNA expression of TSC1, TSC2 and eEF2 relative to the control group. Compared with the control group, HS also led to greater mRNA expression of the CSN1S2 gene. Overall, our study indicates that bovine mammary epithelial cells may have the ability to resist HS damage and continue milk protein synthesis partly through enhanced intracellular amino acid absorption and metabolism and by activating the mTOR signaling pathway during HS.

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