Comparison of effects of HGF and EGF on cellular calcium in rat hepatocytes.
We compared the effects of HGF and EGF on cytoplasmic free calcium concentration, [Ca2+]c, and inositol trisphosphate production in rat hepatocytes. HGF induced a prompt and transient elevation of [Ca2+]c. EGF also induced an immediate increase in [Ca2+]c, the magnitude of which was greater than that by HGF. In contrast, in the presence of 1 microM extracellular calcium EGF increased [Ca2+]c to a lesser extent than HGF. When cells were pretreated with EGF, the effect of HGF on [Ca2+]c was greatly enhanced. However, such enhancement was not observed in medium containing 1 microM extracellular calcium. In hepatocytes prelabeled with [3H]-inositol, both HGF and EGF increased [3H]inositol trisphosphate. HGF and EGF acted synergistically to stimulate production of inositol trisphosphate. These results indicate that both HGF and EGF increase [Ca2+]c by a mechanism involving phosphoinositide turnover and that the actions of HGF and EGF on hepatocyte calcium metabolism are not totally identical.
Mine
T
T
Fourth Department of Internal Medicine, University of Tokyo School of Medicine, Japan.
Kojima
I
I
Ogata
E
E
Nakamura
T
T
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006133:Growth Substances / Q000494:pharmacology*; D017228:Hepatocyte Growth Factor; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D006133:Growth Substances; D004815:Epidermal Growth Factor; D017228:Hepatocyte Growth Factor; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium