The interaction of /sup 125/I-insulin with cultured 3T3-L1 adipocytes: quantitative analysis by the hypothetical grain method

Journal Article · Fri Jul 01 04:00:00 EDT 1983 · J. Histochem. Cytochem.; (United States)

DOI:https://doi.org/10.1177/31.7.6343480· OSTI ID:5394826

Fan, J Y; Carpentier, J L; Van Obberghen, E; Blackett, N M; Grunfeld, C; Gorden, P; Orci, L

The murine 3T3-L1 fibroblast under appropriate incubation conditions differentiates into an adipocyte phenotype. This 3T3-L1 adipocyte exhibits many of the morphologic, biochemical, and insulin-responsive features of the normal rodent adipocyte. Using quantitative electron microscopic (EM) autoradiography we find that, when /sup 125/I-insulin is incubated with 3T3-L1 adipocytes, the ligand at early times of incubation localizes to the plasma membrane of the cell preferentially to microvilli and coated pits. When the incubation is continued at 37 degrees C, /sup 125/I-insulin is internalized by the cells and preferential binding to the villous surface is lost. With the internalization of the ligand, two intracellular structures become labeled, as determined by the method of hypothetical grain analysis. These include large clear, presumably endocytotic, vesicles and multivesicular bodies. Over the first hour of incubation the labeling of these structures increases in parallel, but in the second hour they diverge: the labeling of multivesicular bodies and other lysosomal forms continuing to increase and the labeling of large clear vesicles decreasing. At 3 hours limited but significant labeling occurs in small Golgi-related vesicles that have the typical distribution of GERL. The distinct morphologic features of this cell make it ideal for a quantitative morphologic analysis and allow for an unambiguous view of the sequence of events involved in receptor-mediated endocytosis of a polypeptide hormone. These events are likely to be representative of the processing of insulin by the mature rodent adipocyte.

• Research Organization: Institute of Histology and Embryology, University of Geneva Medical School, Switzerland
• OSTI ID: 5394826
• Journal Information: J. Histochem. Cytochem.; (United States), Journal Name: J. Histochem. Cytochem.; (United States) Vol. 31:7; ISSN JHCYA
• Country of Publication: United States
• Language: English

Related Subjects

550301* -- Cytology-- Tracer Techniques
550801 -- Morphology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADIPOSE TISSUE
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
BODY
CELL CONSTITUENTS
CELL CULTURES
CELL MEMBRANES
CHEMISTRY
CONNECTIVE TISSUE
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
FAT CELLS
FIBROBLASTS
HORMONES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LYSOSOMES
MAMMALS
MEMBRANES
MICE
MORPHOLOGY
NUCLEI
ODD-EVEN NUCLEI
ORGANOIDS
PEPTIDE HORMONES
RADIOISOTOPES
RODENTS
SOMATIC CELLS
TISSUES
VERTEBRATES