Epidermal growth factor precursor in mouse lactating mammary gland alveolar cells

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Molecular Endocrinolgy; (USA)

DOI:https://doi.org/10.1210/mend-3-7-1077· OSTI ID:5102217

Brown, C F; Teng, C T; Pentecost, B T; DiAugustine, R P ^[1]

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1. National Institute of Environmental Health Sciences, Research Triangle Park, NC (USA)

Previous studies have demonstrated that high levels of epidermal growth factor (EGF) occur in human and rodent milk and that oral administration of this polypeptide stimulates rodent gastrointestinal development. It is not known whether EGF in milk originates from cells of the lactating mammary gland or is sequestered from an extramammary source. In the present study, prepro-EGF mRNA (approximately 4.7 kilobases) was detected in the CD-1 mouse mammary gland throughout the period of lactation; by comparison, negligible levels of this EGF transcript were found in the gland during pregnancy. Low levels of EGF immunoreactivity (4-5 ng/g wet wt tissue) were extracted from lactating (day 18) mammary glands with dilute acetic acid. Immunolocalization was evident with antisera to either EGF or two other regions of the EGF precursor in essentially all alveolar cells of the lactating gland. The most prominent staining with antiserum to EGF was observed along the luminal borders of cells; this pattern of cellular staining required proteolytic pretreatment of tissue sections. Western blot analyses of cell membranes isolated from the day 16 lactating mammary gland revealed an EGF-immunoreactive band at about 145K, which was equivalent in size to the EGF precursor found in mouse kidney cell membranes. Despite these findings, labeling of lactating mammary gland mince with L-(35S)methionine and cysteine for up to 4 h did not reveal any specific bands in immunoprecipitates. These cumulative findings suggest that the precursor form of EGF occurs in alveolar cells of lactating mammary gland and that this protein is translocated to the cell membrane.

• OSTI ID: 5102217
• Journal Information: Molecular Endocrinolgy; (USA), Vol. 3:7; ISSN 0888-8809
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GROWTH FACTORS
BIOSYNTHESIS
AUTORADIOGRAPHY
CELL MEMBRANES
CROPS
CYSTEINE
ELECTROPHORESIS
EPIDERMIS
LACTATION
MAMMARY GLANDS
METHIONINE
MICE
PRECURSOR
PREGNANCY
RNA
SULFUR 35
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DRUGS
EPITHELIUM
EVEN-ODD NUCLEI
GLANDS
ISOTOPES
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
MEMBRANES
MITOGENS
NUCLEI
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RODENTS
SKIN
SULFUR ISOTOPES
SYNTHESIS
THIOLS
TISSUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques