Interaction of insulin-like growth factor I with porcine thyroid cells cultured in monolayer

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-121-2-749· OSTI ID:6173955

Saji, M; Tsushima, T; Isozaki, O; Murakami, H; Ohba, Y; Sato, K; Arai, M; Mariko, A; Shizume, K

The interaction of insulin-like growth factor I (IGF-I) with porcine thyroid cells cultured in monolayer was studied. Specific binding of (/sup 125/I)iodo-IGF-I to thyroid cells was a reversible process dependent on the time and temperature of incubation. A steady state was achieved in 18 h at 4 C and averaged 14.2 +/- 2% (mean +/- SD)/10(6) cells. Binding of (/sup 125/I)iodo-IGF-I was inhibited by unlabeled IGF-I; half-maximal inhibition occurred at concentrations of 2-5 ng/ml. Multiplication-stimulating activity (rat IGF-II) and pork insulin had relative potencies of 1:20 and 1:300 compared with IGF-I. Scatchard analysis of binding data revealed a single class of IGF-I receptors with a Ka of 4.3 X 10(10) M-1, 49,000 binding sites were estimated per cell. Affinity cross-linking and autoradiography demonstrated the presence of type I IGF receptors. Thyroid cells also had specific receptors for insulin, but specific binding of (/sup 125/I)iodoinsulin was much lower than that of (/sup 125/I)iodo-IGF-I. Preincubation of thyroid cells with IGF-I or insulin caused a concentration-dependent decrease in (/sup 125/I)iodo-IGF-I binding due to an apparent loss of receptors. Preincubation with epidermal growth factor, fibroblast growth factor, platelet-derived growth factor, or TSH did not alter subsequent binding of (/sup 125/I)iodo-IGF-I. Low concentrations of IGF-I stimulated DNA synthesis and proliferation of thyroid cells and acted synergistically with epidermal growth factor. Multiplication-stimulating activity and insulin had relative potencies in stimulating DNA synthesis comparable to their abilities to inhibit the binding of (/sup 125/I)iodo-IGF-I to thyroid cells.

• Research Organization: Tokyo Women's Medical College, Japan
• OSTI ID: 6173955
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 121:2; ISSN ENDOA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CELL CULTURES
CELL PROLIFERATION
DAYS LIVING RADIOISOTOPES
DNA REPLICATION
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
GLANDS
GROWTH FACTORS
HORMONES
INHIBITION
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MITOGENS
NUCLEI
NUCLEIC ACID REPLICATION
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SWINE
TEMPERATURE DEPENDENCE
THYROID
TIME DEPENDENCE
TRACER TECHNIQUES
VERTEBRATES