scholarly journals Insulin and growth factors stimulate the phosphorylation of a Mr-22000 protein in 3T3-L1 adipocytes

1983 ◽  
Vol 214 (1) ◽  
pp. 11-19 ◽  
Author(s):  
P J Blackshear ◽  
R A Nemenoff ◽  
J Avruch
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Insulin Treatment ◽  
Calf Serum ◽  
Fold Increase ◽  
Foetal Calf Serum ◽  
Heat Stable ◽  
Maximal Stimulation ◽  
Heat Stable Protein ◽  
Epidermal Growth

Insulin, epidermal growth factor (EGF), platelet-derived growth factor, multiplication-stimulating activity and 10% foetal-calf serum each stimulated the phosphorylation of a cytosolic Mr-22000 acidic heat-stable protein in Swiss mouse 3T3-L1 adipocytes. Phosphorylation of this protein was not stimulated by isoprenaline or dibutyryl cyclic AMP. The effect of insulin was maximal (3-fold increase) by 10 min; half-maximal stimulation was observed at 70 pM-insulin. Both [32P]phosphoserine and [32P]phosphothreonine residues were present in the Mr-22000 protein after insulin- and growth-factor-stimulated phosphorylation, but no [32P]phosphotyrosine. The major site of insulin- and EGF-stimulated phosphorylation appeared to be a threonine residue, in contrast with previously studied insulin-stimulated phosphorylation of serine residues. Insulin treatment appeared to result in a shift of the protein toward the anode on isoelectric focusing. Insulin and EGF present simultaneously did not lead to phosphorylation beyond that seen with each hormone singly. We surmise that insulin, EGF and perhaps other growth factors may activate a common protein kinase or inhibit a common protein phosphatase in 3T3-L1 adipocytes which acts on the Mr-22000 protein.

A factor present in fetal calf serum enhances oncogene-induced transformation of rodent fibroblasts

1987 ◽  
Vol 7 (10) ◽  
pp. 3380-3385
Author(s):  
W L Hsiao ◽  
C A Lopez ◽  
T Wu ◽  
I B Weinstein
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Time Course ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Fold Increase ◽  
Fibroblast Cell ◽  
Focus Formation ◽  
Heat Stable

Our previous studies indicated that addition of the tumor promoters 12-O-tetradecanoylphorbol-13-acetate (TPA) or teleocidin to Dulbecco modified Eagle medium supplemented with calf serum enhanced T24-induced focus formation in both the murine C3H 10T1/2 and rat 6 embryo fibroblast cell lines. In the present studies we have found that fetal calf serum (FCS) is more potent than 12-O-tetradecanoylphorbol-13-acetate in enhancing T24-induced focus formation, in terms of the number and size of the foci, in both C3H 10T1/2 and rat 6 cells. Time course studies indicate that FCS can exert this enhancing effect when it is added several days after the transfection with T24 DNA. In rat 6 cells, an 11-fold increase in T24-induced focus formation occurred when the transfected cultures were maintained for only 1 day in 5% FCS, starting 4 days after the transfection. Several known growth factors, including epidermal growth factor, transforming growth factors alpha and beta, insulin, and platelet-derived growth factor, did not enhance T24-induced transformation in these cell systems. Fractionation studies indicate that the factor present in FCS has a molecular weight of about 1,300, is not lipid soluble, and is acid, base, and heat stable. These findings suggest that a factor(s) normally present in serum may enhance the emergence of tumor cells in vivo, by acting in concert with an activated oncogene, during the multistage carcinogenic process.

scholarly journals A factor present in fetal calf serum enhances oncogene-induced transformation of rodent fibroblasts.

1987 ◽  
Vol 7 (10) ◽  
pp. 3380-3385 ◽  
Author(s):  
W L Hsiao ◽  
C A Lopez ◽  
T Wu ◽  
I B Weinstein
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Time Course ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Fold Increase ◽  
Fibroblast Cell ◽  
Focus Formation ◽  
Heat Stable

Our previous studies indicated that addition of the tumor promoters 12-O-tetradecanoylphorbol-13-acetate (TPA) or teleocidin to Dulbecco modified Eagle medium supplemented with calf serum enhanced T24-induced focus formation in both the murine C3H 10T1/2 and rat 6 embryo fibroblast cell lines. In the present studies we have found that fetal calf serum (FCS) is more potent than 12-O-tetradecanoylphorbol-13-acetate in enhancing T24-induced focus formation, in terms of the number and size of the foci, in both C3H 10T1/2 and rat 6 cells. Time course studies indicate that FCS can exert this enhancing effect when it is added several days after the transfection with T24 DNA. In rat 6 cells, an 11-fold increase in T24-induced focus formation occurred when the transfected cultures were maintained for only 1 day in 5% FCS, starting 4 days after the transfection. Several known growth factors, including epidermal growth factor, transforming growth factors alpha and beta, insulin, and platelet-derived growth factor, did not enhance T24-induced transformation in these cell systems. Fractionation studies indicate that the factor present in FCS has a molecular weight of about 1,300, is not lipid soluble, and is acid, base, and heat stable. These findings suggest that a factor(s) normally present in serum may enhance the emergence of tumor cells in vivo, by acting in concert with an activated oncogene, during the multistage carcinogenic process.

Late signals are required for the stimulation of DNA synthesis in rat mammary fibroblasts by growth factors

1996 ◽  
Vol 16 (3) ◽  
pp. 249-263 ◽  
Author(s):  
Hai-Lan Chen ◽  
Philip S. Rudland ◽  
John A. Smith ◽  
David G. Fernig
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Maximal Response ◽  
High Concentration ◽  
Initial Concentration ◽  
Maximal Stimulation ◽  
Epidermal Growth ◽  
Lag Period ◽  
Stimulation Of

Maximal stimulation of DNA synthesis in quiescent rat mammary (Rama) 27 fibroblasts is elicited by epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF) 18 h after the initial addition of the growth factors-the ‘lag’ period. At maximally-stimulating concentrations, EGF and bFGF are interchangeable 9 h after their initial addition. When the initial concentration of growth factor is below that required to elicit a maximal response, it is possible to increase the level of DNA synthesis by increasing the concentration of growth factor 9 h after its initial addition. When the initial concentration of growth factor is high, substitution by a lower concentration of growth factor after 9 h allows a greater proportion of cells to synthesize DNA than would be expected from a continuous low dose of growth factor. Similar results are obtained when both the growth factor and its concentration are changed 9 h after the initial addition of growth factor. However, when EGF at a low concentration is substituted for a high concentration of EGF or bFGF the resulting increase in the levels of DNA synthesis is greater when EGF rather than bFGF is added for a second time. The half-life of the growth-stimulatory signals delivered by EGF and by bFGF 9 h after their initial addition is 1–2 h. These results suggest that to stimulate DNA synthesis: (i) EGF or bFGF must deliver a signal(s) continuously; (ii) the initial signals produced by EGF and bFGF are equivalent; (iii) the signals produced between 9–18 h by EGF may be different to those produced by bFGF.

Stimulation of intestinal epithelial cell proliferation in culture by growth factors in human and ruminant mammary secretions

1987 ◽  
Vol 113 (2) ◽  
pp. 285-290 ◽  
Author(s):  
A. N. Corps ◽  
K. D. Brown
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation ◽  
Factor I ◽  
Maximal Stimulation ◽  
Igf I ◽  
Epidermal Growth ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT Samples of human and ruminant mammary secretions stimulated the proliferation of rat intestinal epithelial (RIE-1) cells in culture. The stimulation was dose-dependent, and samples taken prepartum had greater potency than those taken after parturition. When various hormones and growth factors known to be present in milk were tested, only epidermal growth factor (EGF), insulin and insulin-like growth factor I (IGF-I) stimulated the proliferation of RIE-1 cells. IGF-I was effective at lower concentrations than insulin, and the maximal stimulation induced by each of these two polypeptides was greater than that induced by EGF. The maximal stimulation induced by samples of mammary secretions was similar to that induced by insulin or IGF-I. J. Endocr. (1987) 113, 285–290

Role of prostaglandins in intestinal epithelial restitution stimulated by growth factors

1996 ◽  
Vol 270 (5) ◽  
pp. G757-G762 ◽  
Author(s):  
S. Zushi ◽  
Y. Shinomura ◽  
T. Kiyohara ◽  
T. Minami ◽  
M. Sugimachi ◽  
...  
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Calf Serum ◽  
Nordihydroguaiaretic Acid ◽  
Intestinal Epithelial ◽  
Epithelial Restitution ◽  
Endogenous Prostaglandins ◽  
Epidermal Growth

Mucosal integrity is reestablished after superficial injuries by a rapid resealing process, termed epithelial restitution, that is regulated by several growth factors and cytokines. Growth factors are also known to stimulate the synthesis of endogenous prostaglandins that mediate important functions in intestinal epithelial cells. Therefore, we examined the effect of endogenous eicosanoid production modulators, piroxicam, dexamethasone, and nordihydroguaiaretic acid (NDGA) on intestinal epithelial restitution using two cultured cell wound-resealing models, IEC-6 and Caco-2 cells. Epidermal growth factor, transforming growth factor-beta, hepatocyte growth factor, and fetal calf serum (FCS) accelerated intestinal epithelial restitution, and piroxicam significantly suppressed these stimulatory effects. Dexamethasone mimicked the action of piroxicam. No additive effect of piroxicam and dexamethasone was observed. NDGA did not affect epithelial restitution. Piroxicam abolished the increase in 6-ketoprostaglandin F1 alpha (PGF1 alpha) release induced by FCS. Furthermore, addition of a stable PGI2 analogue, OP-41483 [5(E)-6,9-deoxa-6,9-methylene-15-cyclopentyl-16,17,18,19,20-pen tanor-PGI2], reversed the slowing of epithelial restitution induced by piroxicam. These results suggest that endogenous prostaglandins play an important role in regulating intestinal epithelial restitution.

Modulation of bFGF in lung fibroblasts by TGF-beta and PDGF

1991 ◽  
Vol 261 (6) ◽  
pp. L378-L385 ◽  
Author(s):  
K. T. Goldsmith ◽  
R. B. Gammon ◽  
R. I. Garver
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Calf Serum ◽  
Fold Increase ◽  
Fibroblast Cell ◽  
Lung Fibroblasts ◽  
Tgf Beta ◽  
Human Lung Fibroblast

Growth factors produced by alveolar macrophages are thought to promote the fibroblast proliferation within interstitial spaces of fibrotic lungs. This study investigated the possibility that the macrophage-produced growth factors might modulate the expression of basic fibroblast growth factor (bFGF) by lung fibroblasts. To evaluate this question, bFGF gene expression and protein production were evaluated in normal adult human lung fibroblast cell lines. Under normal culture conditions, the fibroblasts expressed the bFGF gene as two major transcripts (7.1, 3.7 kb). The addition of fetal calf serum (FCS) to serum-starved fibroblasts caused a 5- to 10-fold increase in bFGF expression. Steady-state bFGF expression was increased 108% by platelet-derived growth factor (PDGF) and 602% by transforming growth factor-beta (TGF-beta). Insulin-like growth factor-1 had no significant effect on bFGF expression. Nuclear runoff studies demonstrated that both PDGF and TGF-beta increased the relative rates of bFGF transcription in the fibroblasts. Western blot analysis of lysates from fibroblasts treated with either PDGF or TGF-beta had no detectable increase in bFGF protein above unstimulated controls. However, the simultaneous addition of PDGF and TGF-beta, or FCS, produced a marked increase in bFGF. These experiments show that two growth factors present in the alveolar airspace compartment of fibrotic lungs can promote the expression of bFGF within lung fibroblasts.

Insulin and epidermal growth factor are growth factors for isolated porcine thyroid follicles

1985 ◽  
Vol 110 (1_Suppla) ◽  
pp. S74
Author(s):  
R. GÄRTNER ◽  
W. GREIL ◽  
R. DEMHARTER ◽  
K. HORN
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Epidermal Growth
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