Skip to main content
eScholarship
Open Access Publications from the University of California

Carrier-mediated transport and enzymatic hydrolysis of the endogenous cannabinoid 2-arachidonylglycerol

  • Author(s): Beltramo, M
  • Piomelli, D
  • et al.
Abstract

The human astrocytoma cell line CCF-STTG1 accumulates [3H]2-AG through an Na+- and energy-independent process, with a K(m) of 0.7 ± 0.1 μM. 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 μM, 4.2 ± 0.3 μM and 1.8 ± 0.1 μM, 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 μM) and triacsin C (10 μM), 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. (C) 2000 Lippincott Williams and Wilkins.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View