- Main
Carrier-mediated transport and enzymatic hydrolysis of the endogenous cannabinoid 2-arachidonylglycerol
Abstract
The human astrocytoma cell line CCF-STTGI accumulates [3H]2-AG through an Na(+)- and energy-independent process, with a Km of 0.7 +/- 0.1 microM. Non-radioactive 2-AG, anandamide or the anandamide transport inhibitor 4-hydroxyphenyl arachidonamide inhibit [3H]2-AG uptake with half-maximal inhibitory concentrations (IC50) of 5.5 +/- 1.0 microM, 4.2 +/- 0.3 microM and 1.8 = 0.1 microM, respectively. A variety of lipid transport substrates and inhibitors interfere with neither [3H]2-AG nor [3H]anandamide uptake. These results suggest that 2-AG and anandamide are internalized in astrocytoma cells through a common carrier-mediated mechanism. After incubation with [3H]2-AG, radioactivity is recovered in phospholipids, monoacylglycerols (unmetabolized [3H]2-AG), free fatty acids ([3H]arachidonate) and, to a minor extent, diacylglycerols and triacylglycerols. Arachidonic acid (100 microM) and triacsin C (10 microM), an acyl-CoA synthetase inhibitor, prevent incorporation of [3H]arachidonic acid in phospholipids and significantly reduce [3H]2-AG transport. Thus, the driving force for 2-AG internalization may derive from the hydrolysis of 2-AG to arachidonate and the subsequent incorporation of this fatty acid into phospholipids.
Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.
Main Content
Enter the password to open this PDF file:
-
-
-
-
-
-
-
-
-
-
-
-
-
-