Insulin stimulates turnover of phosphatidylcholine in rat adipocytes.
The present study investigated the effect of insulin on phosphatidylcholine turnover in rat adipocytes labelled to equilibrium with [14C]-choline. Insulin induced a rapid turnover of this major phospholipid that was maximal by 1 min and transient in nature. Following a 1 min stimulation of the cells with insulin at a maximally effective concentration (7 nM), a 4-6% decrease in the percentage of total cellular choline associated with this phospholipid was observed. This reflected a significant transient increase in the percentage of total cellular choline associated with phosphorylcholine, which together with diacylglycerol are the phospholipase C cleavage products of phosphatidylcholine. These effects were observed over a physiological range of insulin concentrations. No effect of insulin on any other choline phospholipid or metabolite (sphingomyelin, lysophophatidylcholine, glycerophosphocholine or choline) was seen. These results suggest that insulin stimulates a phospholipase C-mediated turnover of phosphatidylcholine in rat adipocytes. The rapid nature of this turnover suggests a potential role in signal transduction.
CSIRO Division of Biomolecular Engineering, Parkville, Victoria, Australia.
S L
SL
Macaulay
R G
RG
Larkins
D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002794:Choline / Q000378:metabolism; D004822:Epididymis; D006868:Hydrolysis; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010767:Phosphorylcholine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
D007328:Insulin; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010767:Phosphorylcholine; D010727:Phosphoric Diester Hydrolases; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D002794:Choline