A methodology for radiolabeling of the endocannabinoid 2-arachidonoylglycerol (2-AG)
The metabolic intermediate and endocannabinoid signaling lipid 2-arachidonoylglycerol (2-AG) has not been readily labeled, primarily due to its instability towards rearrangement. We now detail a synthetic method that easily gives tritiated 2-AG from [5,6,8,9,11,12,14,15-3H(N)]arachidonic acid in two...
| Published in: | The Journal of Organic Chemistry |
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| Main Authors: | , , , , , |
| Format: | Text |
| Language: | English |
| Published: |
2011
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| Subjects: | |
| Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3064716 http://www.ncbi.nlm.nih.gov/pubmed/21370840 https://doi.org/10.1021/jo102277q |
| Summary: | The metabolic intermediate and endocannabinoid signaling lipid 2-arachidonoylglycerol (2-AG) has not been readily labeled, primarily due to its instability towards rearrangement. We now detail a synthetic method that easily gives tritiated 2-AG from [5,6,8,9,11,12,14,15-3H(N)]arachidonic acid in two steps. We utilized a short chain 1,3-diacylglycerol and proceeded through the “structured lipid” [5″,6″,8″,9″,11″,12″,14″,15″-3H(N)]2-arachidonoyl-1,3-dibutyrylglycerol, a triacylglycerol that was conveniently deprotected in ethanol with acrylic beads containing Candida antarctica lipase B to give [5″,6″,8″,9″,11″,12″,14″,15″-3H(N)]2-arachidonoylglycerol ([3H]2-AG). The flash chromatographic separation necessary to isolate the labeled 2-acylglycerol [3H]2-AG resulted in only 4% of the rearrangement byproducts that have been a particular problem with previous methodologies. This reliable “kit” method to prepare the radiolabeled endocannabinoid as needed gave tritiated 2-arachidonoylglycerol [3H]2-AG with a specific activity of 200 Ci/mmol for enzyme assays, metabolic studies, and tissue imaging. It has been run on unlabeled materials on over 10 mg scales and should be generally applicable to other 2-acylglycerols. |
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