scholarly journals Characterization and biological activity of relaxin in porcine milk

Reproduction ◽  
2011 ◽  
Vol 141 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Amy-Lynn Frankshun ◽  
Teh-Yuan Ho ◽  
David C Reimer ◽  
Joseph Chen ◽  
Salamia Lasano ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Milk Proteins ◽  
Immunoblot Analysis ◽  
Mammary Tissue ◽  
Early Lactation ◽  
Maternal Circulation ◽  
A Site ◽  
Porcine Milk ◽  
Primary Form

A lactocrine mechanism for delivery of maternally derived relaxin (RLX) into the neonatal circulation as a consequence of nursing was proposed for the pig. Immunoreactive RLX was detected in colostrum and in the serum of newborn pigs only if they were allowed to nurse. Milk-borne RLX concentrations are highest during early lactation (9–19 ng/ml), declining to <2 ng/ml by postnatal day 14. Whether milk-borne RLX is bioactive is unknown. Evidence that RLX concentrations in milk are higher than in maternal circulation in several species suggests the mammary gland as a site of local RLX production. It is unknown whether the porcine mammary gland is a source of RLX. Therefore, objectives were to evaluate RLX bioactivity in porcine milk during the first 2 weeks of lactation, identify the form of RLX in porcine milk, and determine whether mammary tissue from early lactation is a source of milk-borne RLX. Milk RLX bioactivity was determined using anin vitrobioassay in which cAMP production by human embryonic kidney (HEK293T) cells transfected with the human RLX receptor (RXFP1) was measured. RLX bioactivity was highest at lactation day (LD) 0, decreasing to undetectable levels by LD 4. Immunoblot analysis of milk proteins revealed an 18 kDa band, indicating proRLX as the primary form of RLX in porcine milk. ProRLX protein and transcripts were detected in porcine mammary tissue on LD 0 and 7. Results support the lactocrine hypothesis by defining the nature and a potential source for bioactive proRLX in porcine colostrum/milk.

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

THE IN VITRO METABOLISM OF MAMMARY GLAND SLICES IN THE PRESENCE OF POSTERIOR PITUITARY LOBE EXTRACTS RICH IN MELANOPHORE-DISPERSING ACTIVITY

1957 ◽  
Vol 15 (4) ◽  
pp. 366-373 ◽  
Author(s):  
T. R. BRADLEY ◽  
G. M. MITCHELL
Keyword(s):  
Mammary Gland ◽  
Guinea Pigs ◽  
Incubation Medium ◽  
Mammary Glands ◽  
Gas Evolution ◽  
Early Lactation ◽  
Posterior Pituitary ◽  
Rats And Mice ◽  
Posterior Pituitary Lobe

SUMMARY Slices cut from mammary glands of rats and mice during gestation and lactation were incubated in vitro in the presence of pig posterior pituitary lobe extracts rich in melanophore-dispersing ('B') activity. Slices taken in early lactation but not during gestation or late lactation showed increased net gas evolution compared with control slices. Similar tissue from rabbits and guinea-pigs did not give rise to this effect, nor did slices of other tissues taken from lactating rats. The increased net gas evolution was not observed in the absence of glucose from the incubation medium. Treatment of the 'B' extract with NaOH or hypophysectomy of the rats prior to use decreased the response.

Uteroplacental insufficiency alters the mammary gland response to lactogenic hormones in vitro

2008 ◽  
Vol 20 (4) ◽  
pp. 460 ◽  
Author(s):  
Rachael O'Dowd ◽  
Mary E. Wlodek ◽  
Kevin R. Nicholas
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Postnatal Growth ◽  
Mammary Development ◽  
Mammary Tissue ◽  
Sham Surgery ◽  
Uterine Vessel ◽  
Lactogenic Hormones ◽  
Vessel Ligation

Adequate mammary development and coordinated actions of lactogenic hormones are essential for the initiation of lactation. Pregnancies compromised by uteroplacental insufficiency impair mammary development and lactation, further slowing postnatal growth. It is not known whether the initiation of lactation or galactopoesis is compromised. Uteroplacental insufficiency induced in rats by bilateral uterine vessel ligation (Restricted) or sham surgery (Control) on Day 18 of gestation preceded collection of mammary tissue on Day 20 of pregnancy. Mammary explants were cultured with combinations of insulin, cortisol and prolactin and analysed for α-lactalbumin and β-casein gene expression. Mammary tissue from late pregnant Restricted rats had elevated α-lactalbumin, but not β-casein, mRNA, which is consistent with premature lactogenesis resulting from an early decline in peripheral maternal progesterone. Explants from Restricted rats were more responsive to hormone stimulation after 3 days in culture, indicating that compromised galactopoesis, not lactogenesis, most likely leads to the reduced growth of suckled pups.

Transfer of protein antigens into milk after intravenous injection into lactating mice

1986 ◽  
Vol 251 (2) ◽  
pp. E227-E233
Author(s):  
P. R. Harmatz ◽  
D. G. Hanson ◽  
M. K. Walsh ◽  
R. E. Kleinman ◽  
K. J. Bloch ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Bovine Serum ◽  
Trichloroacetic Acid ◽  
Gamma Globulin ◽  
Total Radioactivity ◽  
Mammary Tissue ◽  
Test Interval ◽  
Protein Antigens ◽  
Maternal Circulation ◽  
Beta Lactoglobulin

We investigated the transfer of bovine serum 125I-albumin (125I-BSA), bovine 125I-gamma-globulin (125I-BGG), 125I-ovalbumin (125I-OVA), and 125I-beta-lactoglobulin (125I-BLG) from the blood into the milk of lactating mice. Equal amounts (by weight) of the radiolabeled proteins were injected intravenously into mice 1 wk postpartum. Total radioactivity, trichloroacetic acid-precipitable radioactivity, and specifically immunoprecipitable radioactivity were measured in serum, mammary gland homogenate, and milk. Clearance of immunoreactive OVA (iOVA) and iBLG from the circulation was more rapid than iBSA and iBGG. The radioactivity in mammary tissue associated with BSA and BGG was greater than 70% immunoprecipitable throughout the 4-h test interval; 125I-OVA and 125I-BLG were less than 12% precipitable 1 and 4 h after injection. In milk obtained at 4 h, there was an approximately 10-fold greater accumulation of iBSA or iBGG than of iOVA or iBLG. These experiments demonstrate that protein antigens differ in their ability to transfer from maternal circulation into milk. The transfer into milk appeared to be in proportion to persistence of the antigens in the maternal circulation.

OXYGEN UPTAKE OF RAT MAMMARY TISSUE SLICES

1950 ◽  
Vol 28e (5) ◽  
pp. 217-221 ◽  
Author(s):  
Jules Tuba ◽  
Herbert E. Rawlinson ◽  
Lorna Glen Shaw
Keyword(s):  
Mammary Gland ◽  
Oxygen Uptake ◽  
In Vitro Study ◽  
Female Rats ◽  
Male Rats ◽  
Mammary Tissue ◽  
Oxygen Utilization ◽  
Tissue Slices ◽  
Mammary Gland Tissue

An in vitro study has been made of the oxygen uptake of mammary gland tissue of female rats in various experimental states. Because of the very high proportion of fat in mammary tissue the values of [Formula: see text] are determined on a fat-free as well as a water-free basis, thus providing a more accurate measure of the oxygen consumption of this tissue. The oxygen utilization by mammary gland of pregnant animals is increased approximately three times over the activity in the normal, or resting, gland. This increase is maintained during lactation and a return toward normal levels occurs during postlactational involution. The response to p-phenylenediamine indicated that during lactation the increased energy requirements decreased the reserves of the cytochrome system in mammary tissue. There is a well developed mammary gland in adult male rats; but the average fat content and response to p-phenylenediamine of the tissue are almost identical with values for adult female rats. The use of p-phenylenediamine as a histological stain for the cytochrome system in mammary tissue is described.

Effects of two different forage sources on mammary gland growth, mammary cell turnover and activity in early lactation dairy cows

2015 ◽  
Vol 55 (5) ◽  
pp. 630 ◽  
Author(s):  
Tong Qin ◽  
Haoyu Wang ◽  
Dengpan Bu ◽  
Haisheng Hao ◽  
Dong Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mammary Gland ◽  
Dairy Cows ◽  
Milk Proteins ◽  
Secretory Activity ◽  
Early Lactation ◽  
Cell Turnover ◽  
Mammary Cell ◽  
Proliferation And Apoptosis ◽  
Dietary Treatments

The objective of this study was to evaluate the effects of two different forage sources on mammary gland growth, mammary cell turnover and activity in early lactation dairy cows. Twelve early lactation cows were randomly assigned to a CS (33.8% corn straw as sole forage) or MF diet (3.7% Chinese wildrye + 28.4% alfalfa hay + 26.5% corn silage as mixed forage). All cows were fed from Week –3 to Week 8, and mammary biopsies were taken on 16 days postpartum. Mammary cell proliferation and apoptosis were determined by immunohistology, and genes expression in mammary were detected by real-time PCR. Results showed that cell proliferation, gene expression of milk proteins and proteins involved in the synthesis of milk components did not differ between two dietary treatments (P > 0.05). However, cows fed the MF diet had a higher IGF-1 receptor (IGF-1R) expression (P = 0.02), and lower rate of cell apoptosis (P = 0.003) relative to cows fed the CS diet. Collectively, these results suggest that the mammary secretory activity probably was not affected by the dietary treatments, but high quality and mixed forages led to the increased expression of IGF-1R and a larger number of cells in mammary glands, which may be responsible for the higher milk production in early lactation dairy cows.

scholarly journals Local Insulin-Like Growth Factor-II Mediates Prolactin-Induced Mammary Gland Development

2003 ◽  
Vol 17 (3) ◽  
pp. 460-471 ◽  
Author(s):  
Russell C. Hovey ◽  
Jessica Harris ◽  
Darryl L. Hadsell ◽  
Adrian V. Lee ◽  
Christopher J. Ormandy ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Early Pregnancy ◽  
Insulin Receptors ◽  
Mammary Glands ◽  
Mouse Mammary Gland ◽  
Mammary Epithelial ◽  
Receptor Expression ◽  
Mammary Tissue ◽  
Alveolar Development

Abstract Prolactin (PRL) is a major determinant of mammary epithelial cell proliferation during alveolar development in sexually mature and pregnant mice. To date, it has not been clear whether PRL effects these responses alone or by also invoking the action of autocrine/paracrine growth factors. In this study, we provide evidence that part of the effect of PRL on mammary gland growth is mediated by IGF-II. During sexual maturity and in early pregnancy, the level of IGF-II mRNA in the mammary gland was increased concurrent with increased PRL receptor expression. The level of IGF-II mRNA was reduced in mammary tissue from PRL receptor−/− mice during early pregnancy, and explants of mouse mammary gland and HC11 mammary epithelial cells both increased their expression of IGF-II after exposure to PRL in vitro. These findings coincided with the demonstration that IGF-II stimulated alveolar development in mammary glands in whole organ culture. PRL was most efficacious in stimulating IGF-II gene transcription from promoter 3 of the mouse IGF-II gene in vitro. Insight into the mechanism by which PRL induced IGF-II expression was provided by the fact that it was blocked by the Jak2 inhibitor AG490 and the MAPK inhibitor PD98059. Finally, induction of insulin receptor substrate (IRS)-1 in the mammary glands of PRL-treated mice and induction of IRS-1 and IRS-2 after treatment with PRL plus progesterone indicates that these molecules are induced by PRL as potential signaling intermediates downstream from IGF-I/insulin receptors. Together, these data demonstrate a role for IGF-II as a mediator of PRL action in the mouse mammary gland during ductal branching and alveolar development.

Abundance of solute carrier family 27 member 6 (SLC27A6) in the bovine mammary gland alters fatty acid metabolism

2021 ◽  
Author(s):  
Huimin Zhang ◽  
Ziliang Shen ◽  
Zhendong Yang ◽  
Hui Jiang ◽  
Shuangfeng Chu ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Mammary Tissue ◽  
Mammary Cells ◽  
Solute Carrier Family ◽  
Bovine Mammary Gland ◽  
Solute Carrier

The Milk FA and transcriptome of bovine mammary tissue indicated that LCFA transport into mammary cells during late lactation. In vitro test underscored how FA transport via SLC27A6 could dictate the utilization of FA for TG synthesis versus oxidation.

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