scholarly journals Cellular localisation of GH receptor in the bovine mammary gland during mammogenesis, lactation and involution

2000 ◽  
Vol 166 (3) ◽  
pp. 503-510 ◽  
Author(s):  
F Sinowatz ◽  
D Schams ◽  
S Kolle ◽  
A Plath ◽  
D Lincoln ◽  
...  

We have used immunohistochemistry and non-radioactive in situ hybridisation to localise the GH receptor and its transcript in the bovine mammary gland during mammogenesis, lactation and involution. We found a characteristic pattern of immunoreactive GH (irGH) receptor distribution in the epithelial and stromal compartments during the different stages of mammary gland development: The ductular epithelium showed a distinct staining for irGH receptor during most stages, whereas the alveolar epithelium contained a modest amount of GH receptor during pregnancy which increased during lactation and galactopoiesis. In dry cows, the immunostaining for GH receptors in the alveolar epithelium was very weak or negative. Curiously, the amount of GH receptor mRNA appeared relatively constant during mammogenesis and lactation. The epithelial cells of the alveoli and ducts as well as the endothelial cells showed a distinct signal in our in situ hy! bridisation studies. The predominant localisation of GH receptors in the epithelium of ducts and alveoli is supportive of a role for GH in epithelial differentiation and maintenance. Furthermore, the increased intensity of immunostaining in bovine mammary tissue post partum suggests a direct role for GH receptor in mediating the effect of GH in milk production and secretion.

1990 ◽  
Vol 126 (3) ◽  
pp. R5-R8 ◽  
Author(s):  
D.R. Glimm ◽  
V.E. Baracos ◽  
J.J. Kennelly

ABSTRACT GH receptor messenger RNA (mRNA) was identified and characterized in mammary tissue from normal and GH-treated lactating cows using Northern and in-situ hybridization analyses. One major GH receptor transcript of 4.4 kilobases and a less abundant transcript of 9.2 kilobases were detected in mammary tissue from both normal and GH-treated cows. In-situ hybridization analysis revealed that the GH receptor gene is primarily expressed in the alveolar epithelial cells of mammary tissue. These results are evidence that the lactating mammary gland may synthesize GH receptors. On the basis of these observations it seems likely that the lactating bovine mammary gland is a GH target tissue. This finding challenges the widely accepted view that GH does not directly regulate mammary growth or function.


2001 ◽  
Vol 168 (1) ◽  
pp. 39-48 ◽  
Author(s):  
A Plath-Gabler ◽  
C Gabler ◽  
F Sinowatz ◽  
B Berisha ◽  
D Schams

To study the involvement of the IGFs in mammary development and lactation of the cow, the temporal expressions of IGF-I and -II, its receptor type 1 (IGFR-1), IGF-binding proteins (IGFBPs)-1 to -6 and GH receptor (GHR) mRNA were examined. This was carried out for different stages of mammogenesis, lactogenesis, galactopoiesis and involution in the bovine mammary gland of 26 animals. Furthermore, IGF-I was localised by immunohistochemistry. The highest mRNA concentrations for IGF-I were detected in the mammary tissue of late pregnant heifers (days 255-272) and significantly lower expression was detected during lactogenesis and galactopoiesis. Immunohistochemistry of IGF-I revealed only a weak staining in the epithelium of the ducts during mammogenesis. The epithelium of the alveoli were negative during mammogenesis, lactogenesis and galactopoiesis but displayed distinct IGF-I activity during involution. In the stroma a distinct staining of the cytoplasm of adipocytes and of vascular smooth muscle cells was observed. A certain percentage of fibroblasts (usually 20-30%) were also immunopositive. In contrast, highest expression for IGFR-1 was detected during galactopoiesis and involution. The lowest mRNA concentration for IGFR-1 was found during pregnancy (days 194-213). In general, the expression of IGF-II was not regulated during mammogenesis and lactation, but decreased during involution. The mRNA for the six binding proteins was detected in the bovine mammary gland. The dominant binding proteins were IGFBP-3 and -5. The highest expression of IGFBP-3 was observed during mid-pregnancy and the lowest during late lactation, involution and in non-pregnant heifers. The mRNA for IGFBP-5 increased during late mammogenesis and lactogenesis followed by a decrease thereafter. In general, the mRNA concentrations for IGFBP-2, -4 and -6 were barely detectable during all stages. In contrast, the expression for IGFBP-1 was upregulated in the mammary gland of virgin heifers and increased around the onset of lactation. mRNA for GHR was found during all stages examined without outstanding fluctuations. In conclusion, locally produced IGF-I and -II may mediate mammogenesis. The high mammary IGFR-1 mRNA during lactation suggests a role for peripheral IGF-I in maintenance of lactation. The role of IGFBPs in the mammary gland needs further evaluation.


1990 ◽  
Vol 110 (5) ◽  
pp. 1779-1789 ◽  
Author(s):  
A Kurtz ◽  
F Vogel ◽  
K Funa ◽  
C H Heldin ◽  
R Grosse

The cDNA for a previously described growth inhibitor, designated as mammary-derived growth inhibitor (MDGI) (Grosse, R., and P. Langen. 1989. In Handbook of Experimental Pharmacology. In press) has been cloned from a plasmid library which was derived from terminally differentiated bovine mammary gland. Sequencing of the cDNA showed an open reading frame coding for a protein of 133 amino acids. In six positions differences were found between the sequence determined from the cDNA and that determined previously by amino acid sequence analysis. Northern blot analysis revealed abundant MDGI mRNA in the terminally differentiated mammary gland, whereas in virgin gland, liver or pancreas transcripts were not expressed. By use of in situ hybridization technique transcription of MDGI in the developing bovine mammary gland was analyzed. Increasing amounts of MDGI mRNA were detected in the epithelial cells of embryonic mammary rudiment, in the epithelium of developing lobules and in terminal parts of ducts and lobuloalveolar epithelial cells of differentiated glands. There was a geographical gradient of MDGI mRNA concentration in bovine mammary gland reaching a maximum in the proximal parts of the tissue. An immunohistochemical analysis with different polyclonal and peptide directed antibodies against MDGI confirmed the in situ hybridization data with respect to the tissue-specific and differentiation-dependent MDGI expression in bovine mammary gland. The results suggest a close relationship between MDGI transcription and developmental processes in the normal bovine mammary gland.


Development ◽  
2000 ◽  
Vol 127 (14) ◽  
pp. 3107-3118 ◽  
Author(s):  
A.V. Nguyen ◽  
J.W. Pollard

Involution of the mammary gland following weaning is divided into two distinct phases. Initially, milk stasis results in the induction of local factors that cause apoptosis in the alveolar epithelium. Secondly after a prolonged absence of suckling, the consequent decline in circulating lactogenic hormone concentrations initiates remodeling of the mammary gland to the virgin-like state. We have shown that immediately following weaning TGFbeta3 mRNA and protein is rapidly induced in the mammary epithelium and that this precedes the onset of apoptosis. Unilateral inhibition of suckling and hormonal reconstitution experiments showed that TGFbeta3 induction is regulated by milk stasis and not by the circulating hormonal concentration. Directed expression of TGFbeta3 in the alveolar epithelium of lactating mice using a beta-lactoglobulin promoter mobilized SMAD4 translocation to the nucleus and caused apoptosis of these cells, but not tissue remodeling. Transplantation of neonatal mammary tissue derived from TGFbeta3 null mutant mice into syngenic hosts resulted in a significant inhibition of cell death compared to wild-type mice upon milk stasis. These results provide direct evidence that TGFbeta3 is a local mammary factor induced by milk stasis that causes apoptosis in the mammary gland epithelium during involution.


1968 ◽  
Vol 109 (2) ◽  
pp. 169-176 ◽  
Author(s):  
R. G. Coffey ◽  
F. J. Reithel

1. The particulate form of lactating bovine mammary lactose synthetase activity is shown to be more highly organized than previously reported. 2. A novel method of shattering frozen mammary tissue with effective cell disruption is described. 3. The apparent subcellular distribution of lactose synthetase was shown to reflect the method of homogenization. 4. After mild homogenization particles associated with a high content of intact lactose synthetase activity sedimented in the lysosome size range between 5×104 and 3×105g-min. 5. Lactose synthetase was dissociated and solubilized by VirTis homogenization and ultrasonic treatment. The activities and behaviour of UDP-galactose hydrolase, succinate dehydrogenase, β-glucuronidase and phosphodiesterase I were compared. 6. Inhibition of UDP-galactose hydrolase by UTP and α-lactalbumin was observed.


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.


1981 ◽  
Vol 194 (3) ◽  
pp. 999-1006 ◽  
Author(s):  
L J Burditt ◽  
D Parker ◽  
R K Craig ◽  
T Getova ◽  
P N Campbell

1. The expression of alpha-lactalbumin and casein genes was examined in guinea-pig mammary tissue taken from animals both pre- and post-partum. 2. Analysis of total RNA by RNA excess hybridization with sequence-specific complementary DNA probes demonstrated that alpha-lactalbumin mRNA was present late in pregnancy, and that maximum concentrations were present at parturition. Casein gene transcripts were absent late in pregnancy (62 days), but by parturition were present at concentrations identical to those found at all time points examined throughout lactation. 3. Studies using mammary explants in organ culture showed that tissue from pregnant animals, or animals at parturition, synthesized and secreted only alpha-lactalbumin. After parturition, at the onset of casein synthesis, differential rates of secretion of alpha-lactalbumin and the caseins were observed. 4. The results are discussed in terms of the multiple intracellular mechanisms involved in the regulation of milk protein gene expression in the guinea-pig mammary gland.


1998 ◽  
Vol 65 (2) ◽  
pp. 199-208 ◽  
Author(s):  
DAVID T. CALVERT ◽  
TAE-GYU KIM ◽  
JAI-JUN CHOUNG ◽  
CAROLYNN BURNS ◽  
DAVID B. SHENNAN

The transport of L-glutamine by the lactating rat mammary gland has been investigated using rat mammary tissue explants and the in situ perfused rat mammary gland. L-glutamine uptake by both explants and the perfused mammary gland was via both Na+-dependent and Na+-independent pathways. It appeared that these pathways are situated on the blood-facing aspect of the mammary gland. L-glutamine uptake by both mammary preparations was markedly inhibited by 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid in the absence of external Na+. This is consistent with L-glutamine uptake via system L. The Na+-dependent component(s) of L-glutamine uptake remains to be precisely identified. However, system A can be ruled out on the basis that L-glutamine was not inhibited by (methylamino)isobutyric acid. Mammary tissue concentrates L-glutamine with respect to both milk and plasma: we suggest that the Na+-dependent component(s) of L-glutamine uptake is responsible for generating the intracellular to extracellular concentration gradient.


2005 ◽  
Vol 185 (3) ◽  
pp. 593-603 ◽  
Author(s):  
E E Connor ◽  
D L Wood ◽  
T S Sonstegard ◽  
A F da Mota ◽  
G L Bennett ◽  
...  

Steroid receptors are key transcriptional regulators of mammary growth, development and lactation. Expression of estrogen receptors alpha (ERα) and beta (ERβ), progesterone receptor (PR), and estrogen-related receptor alpha-1 (ERRβ) have been evaluated in bovine mammary gland. The ERRα is an orphan receptor that, in other species and tissues, appears to function in the regulation of estrogen-response genes including lactoferrin and medium chain acyl-CoA dehydrogenase and in mitochondrial biogenesis. Expression of ERα, ERβ, PR and ERRα was characterized in mammary tissue obtained from multiple stages of bovine mammary gland development using quantitative real-time RT-PCR. Expression was evaluated in prepubertal heifers, primigravid cows, lactating non-pregnant cows, lactating pregnant cows and non-lactating pregnant cows (n=4 to 9 animals/stage). In addition, ERα, ERβ, PR and ERRα were mapped to chromosomes 9, 10, 15 and 29 respectively, by linkage and radiation hybrid mapping. Results indicated that expression of ERα, PR and ERRα was largely coordinately regulated and they were present in significant quantity during all physiological stages evaluated. In contrast, ERβ transcripts were present at a very low concentration during all stages. Furthermore, no ERβ protein could be detected in bovine mammary tissue by immunohistochemistry. The ERα and PR proteins were detected during all physiological states, including lactation. Our results demonstrate the presence of ERα, PR and ERRα during all physiological stages, and suggest a functional role for ERRα and a relative lack of a role for ERβ in bovine mammary gland development and lactation.


1991 ◽  
Vol 58 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Ralf Einspanier ◽  
Dieter Schams

SummaryConcentrations of insulin-like growth factor 1 (IGF-1), insulin and growth hormone were measured in the secretion of the bovine mammary gland from day 70 ante partum until 6 d post partum. Highest levels were found during the last 2 weeks ante partum followed by a rapid decrease during the first milkings post partum. The association of IGF-1 with its binding proteins in milk was analysed and striking differences were found in the distribution of bound and free IGF-1. IGF-1 appeared mainly in the bound form (91%) at days 40–2 ante partum. Free IGF-1 preponderated in the first milkings post partum (73%) and changed again to about 85% in the bound form after day 4 post partum. A slightly acidic pH (6·3) of the secretion was correlated with high amounts of free IGF-1. Gel filtration experiments revealed a possible pH-dependent mechanism for the binding of IGF-1 to its binding proteins in milk.


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