IGF-1 activates polyphosphoinositide hydrolysis, protein kinase C isoforms and ERK pathway in cultured neonatal rat cardiac myocytes

S. Lavandero, V. Ferez, R. Foncea, M. Sapag-Hagar, D. Leroilh

Research output: Contribution to journalArticlepeer-review

Abstract

Because IGF- lisa natural cardioprotective which migh; improve cardiac function and stimulates growth and proliferation of carfiac myocytes, there is considerable interest to elucidate the molecular f!iechanisms by which IGF-1 exerts these effects on cardiac myocytes We show here that IGF-1 stimulated polyphosphoinositide turnover (mrw at 30s, 65%) and a rapid translocation of PKC isoforms (a, E srd 8) from the soluble lo tiic paniculate fraction IGF-1 also increased both phospholipid- dependent and Ca2\ phospholipid- dependent PKC activities (max. a 2-fold increase at 5 and 15 min for paniculate and soluble fractions, respectively). IGF-1 promoted translocation of ERK to the nucleus, associated with an activation and tyrosine phosphorylaticn of ERK (max at 5 min, 40% of ERK phosphorylated) Prolonged phorbol ester exposure of cells down-regulated subsequent activation of ERKs by IOF-1, suggesting a role of PKC isoforms in this ERK activation. IGF-1 stimulated protein synthesis rate and increased cardiac myocyte cell size, hypertrophie effects inhibited by PKC and ERK inhibitors. Thus, activation of PKC-ERK pathway appears to be important in the hypertrophie effect of IGF-1 on cardiac myocytes Supported by FONDECYT grants 1950452 and 2950002.

Original languageEnglish (US)
Pages (from-to)A917
JournalFASEB Journal
Volume11
Issue number9
StatePublished - Dec 1 1997

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