Involvement of MAP kinase and c-fos signaling in the inhibition of cell growth by somatostatin

The American Journal of Physiology
H YoshitomiS Seino

Abstract

Somatostatin significantly suppressed cell growth of the mouse insulinoma-derived cell line MIN6. MIN6 cells exhibited high-affinity binding of somatostatin with 50% inhibitory concentration value of 0.9 nM. RNA blot analysis revealed that MIN6 cells expressed only SSTR3 among the five somatostatin receptors so far identified. Treatment of MIN6 cells with somatostatin significantly reduced the serum-induced c-fos expression levels. On the other hand, somatostatin (100 nM) treatment of MIN6 cells cultured in medium containing 10% serum transiently increased c-fos expression levels to 282 +/- 4.7% and then significantly decreased them to 27 +/- 7.6% of the levels before treatment. Mitogen-activated protein (MAP) kinase activity transiently increased to 656 +/- 91.2% and decreased thereafter to 39 +/- 13.3% of the activity before the addition of somatostatin (100 nM) into the medium. In addition, the stimulatory effect of somatostatin on c-fos expression and MAP kinase activity (early effect) was not altered by pertussis toxin (PTX), whereas the suppressive effect of somatostatin on c-fos expression and MAP kinase activity (late effect) was mitigated by PTX. These findings suggest that an inhibition of c-fos expression mediated by...Continue Reading

References

Jan 1, 1992·Proceedings of the National Academy of Sciences of the United States of America·Y YamadaS Seino
Mar 1, 1989·Proceedings of the National Academy of Sciences of the United States of America·C LiebowA V Schally
Dec 15, 1983·The New England Journal of Medicine·S Reichlin
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Citations

May 19, 2018·Nature Reviews. Endocrinology·Patrik Rorsman, Mark O Huising
Aug 6, 1999·Frontiers in Neuroendocrinology·Y C Patel

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