Insulin stimulates hydrolysis of plasmanylinositol-glycan and phosphatidylinositol-glycan in rat adipocytes. Insulin-induced generation of inositol glycan, alkylacylglycerol, and diacylglycerol.
Insulin binding to its receptor has been known to induce hydrolysis of phosphatidylinositol-glycan and release inositol-glycan and diacylglycerol, two putative second messengers of insulin actions. We metabolically labeled and purified PIG in rat cultured adipocytes. The treatment of [3H]glycerol-labeled PIG with phosphatidylinositol-specific phospholipase C released [3H]glycerol-labeled DAG and [3H]glycerol-labeled 1-alkyl,2-acyl-glycerol, suggesting that PIG has not only PIG but also plasmanylinositol-glycan moiety. Insulin induced hydrolysis of PIG/PMIG and generation of IG, DAG, and AAG in a dose-dependent manner. This report shows the first demonstration of insulin-sensitive PMIG in rat adipocytes. These results provide evidence that insulin-induced generation of IG, DAG, and AAG might be early events in the insulin-signaling mechanism in rat adipocytes, and insulin-releasable AAG seems to mediate some actions of insulin.
Third Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
S
S
Suzuki
Y
Y
Taneda
S
S
Hirai
Y
Y
Satoh
T
T
Toyota
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D004075:Diglycerides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D005989:Glycerides / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D006017:Glycolipids / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006868:Hydrolysis; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D004075:Diglycerides; D005989:Glycerides; D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D007328:Insulin; D009227:Myristic Acids; C081751:plasmanylinositol glycan; D019814:Myristic Acid; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D005947:Glucose; D005990:Glycerol; D005690:Galactose