Biochemical and ultrastructural processing of (/sup 125/I)epidermal growth factor in rat epidermis and hair follicles: accumulation of nuclear label

Journal Article · Sun Mar 01 04:00:00 EST 1987 · J. Invest. Dermatol.; (United States)

DOI:https://doi.org/10.1111/1523-1747.ep12465488· OSTI ID:6863385

Green, M R; Mycock, C; Smith, C G; Couchman, J R

Although the intracellular ultrastructural processing of epidermal growth factor (EGF) and its receptor have been described in cell culture systems, very few studies have examined this phenomenon in intact tissues. We have examined the ultrastructural and biochemical handling of (/sup 125/I)EGF in the epidermis and hair follicle bulb of intact, viable, 3- to 5-day-old rat skin the EGF receptor distribution of which has already been documented and in which EGF has been shown to be biologically active. After incubation of explants with 10 nM (/sup 125/I)EGF for 2.5 h at 25 degrees or 37 degrees C, radiolabel was detected over the basal cells of the epidermis and hair follicle outer root sheath, confirming previous light microscope observations. More specifically, silver grains were observed near coated and uncoated plasma membrane and coated membrane invaginations, Golgi apparatus, lysosomal structures, and nuclei. Sodium azide inhibited internalization of label, whereas a series of lysosomal inhibitors (chloroquine, monensin, and iodoacetamide) caused a slight increase in silver grains associated with lysosomal vesicles and a decrease in nuclear label. Biochemical analysis indicated that greater than 35% of radioactivity following incubation at 37 degrees C was in the form of degraded (/sup 125/I)EGF fragments and that inclusion of chloroquine, monensin, and iodoacetamide reduced this value to 20.8%, 8.6%, and 4.0%, respectively. In addition, chloramine T-prepared (/sup 125/I)EGF was found to be covalently cross-linked with low efficiency to a protein having the molecular weight of the EGF receptor. These data are discussed in the light of the effects of EGF on epithelial cell proliferation in skin.

• Research Organization: Colworth Lab., Sharnbrook, England
• OSTI ID: 6863385
• Journal Information: J. Invest. Dermatol.; (United States), Journal Name: J. Invest. Dermatol.; (United States) Vol. 3; ISSN JIDEA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
BODY
CELL CONSTITUENTS
CELL NUCLEI
CELL PROLIFERATION
CHEMICAL REACTIONS
CHEMISTRY
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EPIDERMIS
EPITHELIUM
HAIR
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LYSOSOMES
MAMMALS
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PEPTIDE HORMONES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SKIN
TISSUES
VERTEBRATES