Δ9-Tetrahydrocannabinol induces endocannabinoid accumulation in mouse hepatocytes: antagonism by Fabp1 gene ablation.

The Journal of Lipid Research “Phytocannabinoids, such as Δ9tetrahydrocannabinol (THC), bind and activate cannabinoid (CB) receptors, thereby “piggy-backing” on the same pathway’s endogenous endocannabinoids (ECs).

The recent discovery that liver fatty acid binding protein-1 (FABP1) is the major cytosolic “chaperone” protein with high affinity for both Δ9-THC and ECs suggests that Δ9-THC may alter hepatic EC levels.

Therefore, the impact of Δ9-THC or EC treatment on the levels of endogenous ECs, such as N-arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG), was examined in cultured primary mouse hepatocytes from WT and Fabp1 gene-ablated (LKO) mice. Δ9-THC alone or 2-AG alone significantly increased AEA and especially 2-AG levels in WT hepatocytes. LKO alone markedly increased AEA and 2-AG levels. However, LKO blocked/diminished the ability of Δ9-THC to further increase both AEA and 2-AG. In contrast, LKO potentiated the ability of exogenous 2-AG to increase the hepatocyte level of AEA and 2-AG.

These and other data suggest that Δ9-THC increases hepatocyte EC levels, at least in part, by upregulating endogenous AEA and 2-AG levels.

This may arise from Δ9-THC competing with AEA and 2-AG binding to FABP1, thereby decreasing targeting of bound AEA and 2-AG to the degradative enzymes, fatty acid amide hydrolase and monoacylglyceride lipase, to decrease hydrolysis within hepatocytes.”

https://www.ncbi.nlm.nih.gov/pubmed/29414765

http://www.jlr.org/content/59/4/646

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