The insulin receptor as a transmitter of a mitogenic signal in Chinese hamster ovary CHO-K1 cells

Journal Article · Fri Dec 01 04:00:00 EST 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.23.9294· OSTI ID:6855383

Mamounas, M; Gervin, D; Englesberg, E ^[1]

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1. Univ. of California, Santa Barbara (USA)

Insulin is the only hormone required for continued growth of Chinese hamster ovary CHO-K1 cells in the defined medium M-F12. When CHO-K1 cells are incubated in M-F12 without insulin for 48-72 hr, the cells accumulate in G{sub 1}. In response to physiological concentrations of insulin an 18-fold increase in rate of DNA synthesis occurs due to cells entering S phase after an 8- to 10-hr lag; cell division begins after 24 hr. The inhibitory effect of actinomycin D and 5,6-dichlorobenzimidazole riboside indicates that RNA synthesis is required for progression to S phase. CHO-K1 cells possess insulin receptors, and the insulin effect results from insulin binding to its own receptor: (i) binding occurs at physiological insulin concentrations with a half-maximal stimulation at {approx} 14 ng/ml. (ii) At insulin concentrations used, insulin-like growth factor I and II (IGF-I and IGF-II) have little or no effect. (iii) Scatchard analysis of {sup 125}I-labeled insulin binding shows the curvilinear response typical of insulin. (iv) The K{sub d} for the so-called high-affinity binding site and the K{sub e} are characteristic of the insulin receptor. (v) At the minimal insulin concentrations that stimulate growth, IGF-I and IGF-II compete poorly with insulin for insulin binding, insulin competes poorly with IGF-I for IGF-I binding, and affinity labeling with {sup 125}I-labeled insulin identifies as polypeptide typical of the {alpha} subunit of the insulin receptor.

• OSTI ID: 6855383
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 86:23; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACTINOMYCIN
ANIMAL CELLS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
ANTIMITOTIC DRUGS
ANTINEOPLASTIC DRUGS
AZOLES
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CELL CYCLE
CELL DIVISION
CHO CELLS
CYTOLOGICAL TECHNIQUES
DAYS LIVING RADIOISOTOPES
DNA REPLICATION
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
GROWTH
GROWTH FACTORS
HETEROCYCLIC COMPOUNDS
HORMONES
IMIDAZOLES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MEMBRANE PROTEINS
MITOGENS
MITOSIS
NUCLEI
NUCLEIC ACID REPLICATION
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDE HORMONES
PROTEINS
RADIOISOTOPES
RADIORECEPTOR ASSAY
REACTION KINETICS
RECEPTORS
TRACER TECHNIQUES