Hepatic binding and uptake kinetics of epidermal growth factor: studies with isolated rat hepatocytes

Journal Article · Mon Feb 16 04:00:00 EST 1987 · Life Sci.; (United States)

DOI:https://doi.org/10.1016/0024-3205(87)90270-0· OSTI ID:5653348

Rush, G F; Alberts, D

Hepatocytes are known to bind and internalize a variety of small molecular weight proteins by a process known as receptor-mediated endocytosis (RME). The purpose of this investigation was to characterize the binding and uptake kinetics of a small protein known to be taken up by the liver by RME, epidermal growth factor (EGF), using suspensions of freshly isolated rat hepatocytes. Rat hepatocytes accumulated /sup 125/I-EGF (90pM) in a temperature-dependent fashion. Isolated hepatocytes incubated at 37/sup 0/C with /sup 125/I-EGF began to release a TCA-soluble radiolabeled material into the incubation medium with a lag period of 20 min. EGF uptake by isolated hepatocytes was linear for only 60 seconds and displayed saturation kinetics. Hepatocytes incubated at 4/sup 0/C bound, but did not internalize, EGF. Under these conditions, EGF binding was saturable at concentrations above 8 nM. A Scatchard analysis revealed that the average number of receptors per hepatocyte was 7.7 x 10/sup 4/ with a dissociation constant of 2.6 nM. These data demonstrate that freshly isolated hepatocytes are capable of binding, internalizing and metabolizing EGF and thus are a good model to study RME of small molecular weight proteins. 15 references, 5 figures.

• Research Organization: Smith Kline and French Labs., Philadelphia, PA
• OSTI ID: 5653348
• Journal Information: Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 40:7; ISSN LIFSA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MODELS
BODY
DATA
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EPIDERMIS
EPITHELIUM
EXPERIMENTAL DATA
GROWTH FACTORS
INFORMATION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIVER CELLS
MAMMALS
MEMBRANE PROTEINS
METABOLISM
MITOGENS
MOLECULAR WEIGHT
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SKIN
SOMATIC CELLS
TEMPERATURE DEPENDENCE
TISSUES
TRACER TECHNIQUES
VERTEBRATES