scholarly journals Transforming growth factor-alpha stimulates proliferation of mammotrophs and corticotrophs in the mouse pituitary

2000 ◽  
Vol 165 (2) ◽  
pp. 493-501 ◽  
Author(s):  
S Oomizu ◽  
J Honda ◽  
S Takeuchi ◽  
T Kakeya ◽  
T Masui ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Growth Factor ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Receptor Expression ◽  
Pcr Analysis ◽  
Transforming Growth Factor Alpha ◽  
Pituitary Cells ◽  
Factor Alpha ◽  
Mouse Pituitary

Oestrogen stimulates the proliferation of pituitary cells. The present study was designed to clarify the involvement of transforming growth factor-alpha (TGF-alpha) in the oestrogen-induced growth of mouse pituitary cells in vitro. Anterior pituitary cells obtained from ICR male mice were cultured in a primary serum-free culture system. Proliferation of pituitary cells was detected by monitoring the cellular uptake of bromodeoxyuridine. Secretory cell types were immunocytochemically determined. Treatment with TGF-alpha (0.1 and 1 ng/ml) for 5 days stimulated cell proliferation. Since TGF-alpha binds to the epidermal growth factor (EGF) receptor, this action may be exerted through the EGF receptor. Oestradiol-17beta (OE(2), 10(-)(9) M) stimulated mammotrophic and corticotrophic cell proliferation. RG-13022, an EGF receptor inhibitor, inhibited the cell proliferation induced by EGF or OE(2), showing that the EGF receptor was involved in the growth response in mammotrophs and corticotrophs. Treatment with antisense TGF-alpha oligodeoxynucleotide (ODN) inhibited the cell proliferation induced by OE(2), but treatment with antisense EGF ODN did not. RT-PCR analysis revealed that OE(2) stimulated TGF-alpha mRNA and EGF receptor mRNA expression. These results indicate that TGF-alpha mediates the stimulatory effect of oestrogen on the pituitary cell proliferation in a paracrine or autocrine manner, and that EGF receptor expression is stimulated by oestrogen.

scholarly journals Substitution of lysine for arginine at position 42 of human transforming growth factor-alpha eliminates biological activity without changing internal disulfide bonds.

1989 ◽  
Vol 9 (9) ◽  
pp. 4083-4086 ◽  
Author(s):  
D Defeo-Jones ◽  
J Y Tai ◽  
G A Vuocolo ◽  
R J Wegrzyn ◽  
T L Schofield ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Receptor Binding ◽  
Disulfide Bonds ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Receptor Interaction ◽  
Composition Analysis ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

Transforming growth factor-alpha (TGF-alpha) is a growth-promoting protein that binds to the epidermal growth factor (EGF) receptor. To identify critical residues that govern TGF-alpha-EGF receptor binding, we prepared site-specific substitution mutants of TGF-alpha. Mutant proteins were tested in receptor-binding and mitogenesis assays. Semiconservative substitutions at positions 4, 12, 18, and 45 decreased biological activity 2.1- to 14-fold. The conservative substitution of lysine for arginine at position 42 completely eliminated biological activity. Amino acid composition analysis of proteolytic fragments from TGF-alpha and the Lys-42 mutant indicated that these proteins contained the same disulfide bonds. These studies suggest that arginine 42 may be a contact point for TGF-alpha-EGF receptor interaction.

Transforming growth factor alpha in developing rats

1990 ◽  
Vol 259 (2) ◽  
pp. E256-E260 ◽  
Author(s):  
P. I. Brown ◽  
R. Lam ◽  
J. Lakshmanan ◽  
D. A. Fisher
Keyword(s):  
Growth Factor ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Neuronal Cell ◽  
Late Gestation ◽  
Transforming Growth Factor Alpha ◽  
Lung Maturation ◽  
Liver And Kidney ◽  
Epidermal Growth ◽  
Factor Alpha

Transforming growth factor-alpha (TGF-alpha) concentrations were measured in lung, brain, liver, and kidney of rats at three different ages (20 days gestation and 9 and 50 days postnatal). TGF-alpha concentrations were maximal in the lung and brain by 20 days of gestation and showed minimal changes during nursing (day 9) and young adulthood (day 50). The liver, which also showed maximal TGF-alpha concentration by 20 days of gestation, demonstrated a progressive reduction with age to nadir values in the young adult. In contrast to the pattern in other tissues, kidney had the lowest concentration of TGF-alpha in late gestation and showed an increase by 50 days of age. As TGF-alpha acts via the epidermal growth factor (EGF) receptor, its function in development may be analogous to that of EGF. Thus TGF-alpha may have a role in lung maturation and postinjury repair, liver repair and regeneration, and neuronal cell growth.

scholarly journals Transforming growth factor-alpha (TGF-alpha) in human bone marrow: demonstration of TGF-alpha in erythroblasts and eosinophilic precursor cells and of epidermal growth factor receptors in blastlike cells of myelomonocytic origin

Blood ◽  
1995 ◽  
Vol 85 (9) ◽  
pp. 2385-2392 ◽  
Author(s):  
TM Walz ◽  
C Malm ◽  
BK Nishikawa ◽  
A Wasteson
Keyword(s):  
Monoclonal Antibody ◽  
Bone Marrow ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Precursor Cells ◽  
Transforming Growth Factor Alpha ◽  
Epidermal Growth ◽  
Factor Alpha

The expression of transforming growth factor-alpha (TGF-alpha) in human differentiating leukemic cell lines and in circulating human eosinophils prompted the search for an analogous function in normal human bone marrow (BM) cells. Immunohistochemistry, using a monoclonal antibody directed to the mature form of the TGF-alpha molecule, showed TGF-alpha on the erythroblasts of normal donors. This novel property of erythroid cells was found on cells at all stages of maturation, most clearly on nucleated forms but to some extent also on erythrocytes within the BM. The presence of membrane-bound TGF-alpha on erythroblasts was confirmed by immunomagnetic cell sorting with polyclonal TGF-alpha antibodies; the recovered cells consisted almost entirely of erythroblasts. Using another monoclonal antibody directed to TGF-alpha, immunohistochemistry showed a different pattern of positive cells including eosinophilic precursor cells, in accordance with earlier findings in blood eosinophils. In addition, the TGF-alpha immunoreactivity was shown in promyelocytes and neutrophilic myelocytes. The presence of epidermal growth factor (EGF) receptor mRNA in BM cells was demonstrated by reverse transcription polymerase chain reaction, whereas EGF receptor-carrying cells were recognized by immunohistochemistry, using polyclonal antibodies directed to the cytoplasmic part of the EGF receptor. The EGF receptor-positive cell constituted about 3% of the nucleated BM cell population. It was classified as a blastlike cell of myelomonocytic origin by morphologic criteria and CD68 positivity. Our results may indicate a novel function of TGF-alpha in erythrocytic differentiation.

scholarly journals Chicken epidermal growth factor (EGF) receptor: cDNA cloning, expression in mouse cells, and differential binding of EGF and transforming growth factor alpha.

1988 ◽  
Vol 8 (5) ◽  
pp. 1970-1978 ◽  
Author(s):  
I Lax ◽  
A Johnson ◽  
R Howk ◽  
J Sap ◽  
F Bellot ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Alpha ◽  
3T3 Cells ◽  
Epidermal Growth ◽  
Factor Alpha ◽  
Differential Binding ◽  
Nih 3T3

The primary structure of the chicken epidermal growth factor (EGF) receptor was deduced from the sequence of a cDNA clone containing the complete coding sequence and shown to be highly homologous to the human EGF receptor. NIH-3T3 cells devoid of endogenous EGF receptor were transfected with the appropriate cDNA constructs and shown to express either chicken or human EGF receptors. Like the human EGF receptor, the chicken EGF receptor is a glycoprotein with an apparent molecular weight of 170,000. Murine EGF bound to the chicken receptor with approximately 100-fold lower affinity than to the human receptor molecule. Surprisingly, human transforming growth factor alpha (TGF-alpha) bound equally well or even better to the chicken EGF receptor than to the human EGF receptor. Moreover, TGF-alpha stimulated DNA synthesis 100-fold better than did EGF in NIH 3T3 cells that expressed the chicken EGF receptor. The differential binding and potency of mammalian EGF and TGF-alpha by the avian EGF receptor contrasts with the similar affinities of the mammalian receptor for the two growth factors.

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