DEMONSTRATION OF MAMMOTROPHIC ACTIVITY OF THE MOUSE PLACENTA IN ORGAN CULTURE AND BY TRANSPLANTATION

1970 ◽  
Vol 48 (1) ◽  
pp. 99-107 ◽  
Author(s):  
K. KOHMOTO ◽  
H. A. BERN

SUMMARY Mammotrophic (i.e. mammogenic and/or lactogenic) activity of mouse placentae of different stages (4–19 days of pregnancy) was examined using organ co-culture of placental explants with mammary tissue. The test mammary tissues were taken from midpregnant (11–12 days) nulliparous A/Crgl mice and cultured in a synthetic medium (Waymouth's) supplemented with insulin (5 μg/ml) and aldosterone (1 μg/ml). The responses of mammary gland to placental explants were judged histologically, and were compared with those seen after the addition of ovine prolactin (5 μg/ml). With placentae from 6- to 19-day pregnant animals, distinct mammotrophic activity was seen, with the appearance of eosinophilic secretion in the mammary alveolar lumina, whereas with 4- or 5-day-old 'placentae', no mammotrophic activity was detected. Inasmuch as growth hormone does not substitute for prolactin in mammary gland development and function in the A/Crgl mouse, it can be concluded that a prolactin-like factor is present in the mouse placenta. The influence of placentae on mammary gland was further analysed by transplantation of placental fragments to mammary fat pads. Local lobuloalveolar development was prominent in some instances in the area around the placental transplants.

2021 ◽  
Author(s):  
Arianna P. Bartlett ◽  
Gerlinde R. Van de Walle

ABSTRACTMammary organoid (MaO) models are only available for a few traditional model organisms, limiting our ability to investigate mammary gland development and cancer across the diverse taxa of mammals. For example, horses are mammals with a similar mammary anatomy and function as humans, but they have a remarkably low incidence of mammary cancer, making the development of MaOs in non-traditional model organisms attractive, particularly in comparative cancer research. This study established equine mammary organoids (EqMaOs) from mammary gland tissue fragments and evaluated parameters including diameter, budding, and growth stage in non-budding EqMaOs, in cultures with increasing concentrations of epidermal growth factor (EGF), a key growth factor implicated in mammary gland development. Our findings showed that EqMaO diameter is not influenced by EGF concentration, whereas number of EqMaOs with budding and stage in non-budding EqMaOs are positively influenced by increasing EGF concentration. EqMaOs also formed protrusions with putative functions, including organoid fusion and sensory functions. We further characterized EqMaOs by the presence of myoepithelial and luminal cells using immunohistochemistry and used the hormone prolactin to stimulate milk secretion, as illustrated by β-lactoglobulin expression, in these EqMaOs. Additionally, we showed that our method to establish MaOs is widely applicable to additional non-traditional mammalian model organisms such as cat, pig, deer, rabbit, and prairie vole. Collectively, MaO models across species will be a useful tool for comparative developmental and cancer studies.Summary statementMammary organoids can be established from various mammals by embedding mammary tissue fragments into a 3D matrix, providing a high-throughput, physiologically accurate model for comparative studies centered on mammary gland development and cancer.


PLoS ONE ◽  
2014 ◽  
Vol 9 (7) ◽  
pp. e101546 ◽  
Author(s):  
Michael K. G. Stewart ◽  
Isabelle Plante ◽  
John F. Bechberger ◽  
Christian C. Naus ◽  
Dale W. Laird

2003 ◽  
Vol 177 (2) ◽  
pp. 305-317 ◽  
Author(s):  
D Schams ◽  
S Kohlenberg ◽  
W Amselgruber ◽  
B Berisha ◽  
MW Pfaffl ◽  
...  

It is now well established that oestrogen and progesterone are absolutely essential for mammary gland development. Lactation can be induced in non-pregnant animals by sex steroid hormone treatment. Most of the genomic actions of oestrogens are mediated by two oestrogen receptors (ER)-alpha and ERbeta, and for gestagens in ruminants by the progesterone receptor (PR). Our aim was the evaluation of mRNA expression and protein (localisation and Western blotting) during mammogenesis, lactogenesis, galactopoiesis (early, middle and late) and involution (8, 24, 28, 96-108 h and 14-28 days after the end of milking) in the bovine mammary gland (total no. 53). During these stages, the mRNA was assessed by means of real-time RT-PCR (LightCycler). The protein for ERalpha, ERbeta and PR was localised by immunohistochemistry and Western blotting. The mRNA expression results indicated the existence of ERalpha, ERbeta and PR in bovine mammary gland. Both ERalpha and PR are expressed in fg/ micro g total RNA range. The highest mRNA expression was found for ERalpha and PR in the tIssue of non-pregnant heifers, followed by a significant decrease to a lower level at the time of lactogenesis with low concentrations remaining during lactation and the first 4 weeks of involution. In contrast, the expression of ERbeta was about 1000-fold lower (ag/ micro g total RNA) and showed no clear difference during the stages examined, with a significant increase only 2-4 weeks after the end of milking. Immunolocalisation for ERalpha revealed a strong positive staining in nuclei of lactocytes in non-pregnant heifers, became undetectable during pregnancy, lactogenesis and lactation, and was again detectable 14-28 days after the end of milking. In contrast, PR was localised in the nuclei of epithelial cells in the mammary tIssue of non-pregnant heifers, in primigravid animals, and during late lactation and involution. During lactogenesis, peak and mid lactation, fewer nuclei of epithelial cells were positive, but increased staining of the cytoplasm of epithelial cells was obvious. ERalpha and ERbeta protein was found in all mammary gland stages examined by Western blotting. In contrast to mRNA expression, the protein signal for ERalpha was weaker in the tIssue of non-pregnant heifers and during involution (4 weeks). ERbeta protein showed a stronger signal (two isoform bands) in non-pregnant heifers and 4 weeks after the end of milking. This correlated with the mRNA expression data. Three isoforms of PR (A, B and C) were found by Western blotting in the tIssue of non-pregnant heifers, but only isoform B remained during the following stages (lactogenesis, galactopoiesis and involution). In conclusion, the mRNA expression and protein data for ER and PR showed clear regulatory changes, suggesting involvement of these receptors in bovine mammary gland development and involution.


1997 ◽  
Vol 188 (1) ◽  
pp. 134-146 ◽  
Author(s):  
Roel Q.J. Schaapveld ◽  
Jan T.G. Schepens ◽  
Gertraud W. Robinson ◽  
Joline Attema ◽  
Frank T.J.J. Oerlemans ◽  
...  

2021 ◽  
Vol 7 (4) ◽  
pp. 78
Author(s):  
Artem P. Dysin ◽  
Olga Y. Barkova ◽  
Marina V. Pozovnikova

Milk is an integral and therefore complex structural element of mammalian nutrition. Therefore, it is simple to conclude that lactation, the process of producing milk, is as complex as the mammary gland, the organ responsible for this biochemical activity. Nutrition, genetics, epigenetics, disease pathogens, climatic conditions, and other environmental variables all impact breast productivity. In the last decade, the number of studies devoted to epigenetics has increased dramatically. Reports are increasingly describing the direct participation of microRNAs (miRNAs), small noncoding RNAs that regulate gene expression post-transcriptionally, in the regulation of mammary gland development and function. This paper presents a summary of the current state of knowledge about the roles of miRNAs in mammary gland development, health, and functions, particularly during lactation. The significance of miRNAs in signaling pathways, cellular proliferation, and the lipid metabolism in agricultural ruminants, which are crucial in light of their role in the nutrition of humans as consumers of dairy products, is discussed.


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