Effects of betaine on ethanol-stimulated secretion of IGF-I and IGFBP-1 in rat primary hepatocytes： involvement of p42/44 MAPK activation

• Published in: World journal of gastroenterology : WJG 2006-03, Vol.12 (11), p.1718-1722
• Main Authors: Lee, Myeong Soo, Kim, Myung-Sunny, Park, Soo Young, Kang, Chang-Won
• Format: Article
• Language: English
• Subjects: Animals; Basic Research; Betaine - pharmacology; Blotting, Western; Cells, Cultured; Enzyme Activation - drug effects; Enzyme Activation - physiology; Ethanol - pharmacology; Flavonoids - pharmacology; Hepatocytes - drug effects; Hepatocytes - metabolism; Hepatocytes - physiology; Insulin-Like Growth Factor Binding Protein 1 - metabolism; Insulin-Like Growth Factor Binding Protein 1 - physiology; Insulin-Like Growth Factor I - metabolism; Insulin-Like Growth Factor I - physiology; Male; Mitogen-Activated Protein Kinase 1 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 1 - physiology; Mitogen-Activated Protein Kinase 3 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 3 - physiology; p42; p44; Radioimmunoassay; Rats; Rats, Sprague-Dawley; 三甲铵乙内酯; 甜菜碱; 肝细胞
• ISSN: 1007-9327; 2219-2840
• DOI: 10.3748/wjg.v12.i11.1718

AIM： To evaluate the effects of betaine on the ethanolinduced secretion of IGF-I and IGFBP-1 using radioimrnunoassay and Western blotting, respectively, in primary cultured rat hepatocytes. METHODS： Hepatocytes isolated from male SpragueDawley rats were incubated with various concentrations of ethanol and PD98059 procedures. The hepatocytes were also treated with different doses of betaine （10^-5, 10^-4, and 10^-3 mol/L）. We measured IGF-I and IGFBP-1 using radioimmunoassay and Western blotting, respectively. RESULTS： The ethanol-induced inhibition of IGF-I secretion was attenuated by betaine in a concentration-dependent manner in primary cultured rat hepatocytes. At 10^-3 mol/L, betaine significantly increased IGF-I secretion but decreased IGFBP-1 secretion. In addition, p42/44 rnitogen-activated protein kinase （MAPK） activity was accelerated significantly from 10 min to 5 h after treatment with 10^-3 mol/L betaine. Furthermore, the changes in IGF-1 and IGFBP-1 secretion resulting from the increased betaine-induced p42/44 MAPK activity in primary cultured rat hepatocytes was blocked by treatment with the MAPK inhibitor PD98059. Betaine treatment blocked the ethanol-induced inhibition of IGF-I secretion and p42/44 MAPK activity, and the ethanol-induced increase in IGFBP-1 secretion.CONCLUSION： Betaine modulates the secretion of IGF-I and IGFBP-1 via the activation of p42144 MAPK in primary cultured rat hepatocytes. Betaine also alters the MAPK activations induced by ethanol.