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Regulation of Gene Expression in the Bovine Mammary Gland by Ovarian Steroids
- Source :
- Journal of Dairy Science. 90:E55-E65
- Publication Year :
- 2007
- Publisher :
- American Dairy Science Association, 2007.
-
Abstract
- It is well established that estrogen is required for mammary epithelial cell proliferation and ductal development in the growing animal, and that lobuloalveolar development during gestation is dependent on progesterone. The effects of these steroid hormones on gene expression in the mammary gland are mediated primarily by their respective nuclear hormone receptors, which function as hormone-bound transcription factors. To gain insight into how estrogen and progesterone regulate mammary gland growth and function in cattle, we and others have characterized the expression patterns of their cognate nuclear hormone receptors in the bovine mammary gland throughout development, pregnancy, and lactation. This work has identified a lack of expression of estrogen receptor beta and a greater abundance of progesterone receptor during lactation in the bovine mammary gland, compared with the rodent gland. We speculate that interactions among the estrogen receptor isoforms that regulate progesterone receptor expression may contribute to these species differences. Further, demonstrated expression of substantial quantities of estrogen receptor within the prepubertal bovine mammary fat pad, along with coordinated insulin-like growth factor-I expression, suggests that this tissue may stimulate parenchymal growth via an estrogen-responsive paracrine mechanism. In addition, the recent availability of bovine genomic sequence information and microarray technologies has permitted the study of global gene expression in the mammary gland in response to the steroid environment. We have identified more than 100 estrogen-responsive genes, of which the majority are novel estrogen gene targets. Estrogen-induced changes in gene expression were consistent with increased mammary epithelial cell proliferation, increased extracellular matrix turnover in parenchyma, and increased extracellular matrix deposition in the fat pad. A comparison of estrogen-responsive genes in the mammary glands of humans, mice, and cattle suggests considerable variation among species, as well as potential differences in regulatory elements in common estrogen receptor gene targets. Continuing studies using advanced molecular techniques should assist in elucidating the complex regulation of mammary function at the transcript level.
- Subjects :
- medicine.medical_specialty
medicine.drug_class
Mammary gland
Estrogen receptor
Biology
Mammary Glands, Animal
Pregnancy
Internal medicine
Progesterone receptor
Genetics
medicine
Animals
Lactation
Protein Isoforms
Progesterone
Estrogen receptor beta
Estrogens
Microarray Analysis
Endocrinology
medicine.anatomical_structure
Gene Expression Regulation
Receptors, Estrogen
Nuclear receptor
Estrogen
Cattle
Female
Animal Science and Zoology
Estrogen-related receptor gamma
Receptors, Progesterone
Estrogen receptor alpha
Food Science
Subjects
Details
- ISSN :
- 00220302
- Volume :
- 90
- Database :
- OpenAIRE
- Journal :
- Journal of Dairy Science
- Accession number :
- edsair.doi.dedup.....a7be9ae7b0da13c227e6ee28c8554cc2