Expression and localisation of @entity2931 and @entity1420 receptors in the XXXX mammary gland during development, function and involution.

@entity1420 @entity2931 @entity40664 @entity134 @entity40665 @entity291
It is now well established that @entity2931 and @entity1420 are absolutely essential for mammary gland development. Lactation can be induced in non-pregnant animals by sex @entity134 hormone treatment. Most of the genomic actions of @entity2931 are mediated by two @entity2931 receptors ( @entity40664 and @entity40665 , and for gestagens in ruminants by the @entity1420 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 @entity291 mammary gland (total no. 53). During these stages, the mRNA was assessed by means of real-time RT-PCR (LightCycler). The protein for @entity40664 , @entity40665 and PR was localised by immunohistochemistry and Western blotting. The mRNA expression results indicated the existence of @entity40664 , @entity40665 and PR in @entity291 mammary gland. Both @entity40664 and PR are expressed in fg/ micro g total RNA range. The highest mRNA expression was found for @entity40664 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 @entity40665 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 @entity40664 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. @entity40664 and @entity40665 protein was found in all mammary gland stages examined by Western blotting. In contrast to mRNA expression, the protein signal for @entity40664 was weaker in the tIssue of non-pregnant heifers and during involution (4 weeks). @entity40665 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 @entity291 mammary gland development and involution.
