A floxed neo cassette was inserted upstream of exon 3. An additional loxP site was inserted downstream of exon 4. Cre-mediated recombination removed the neo cassette and exons 3 and 4. Monoacylglycerol hydrolase (MGH) activity assays confirmed the reduction in neutral MGH activity in white adipose tissue and liver and almost undetectable levels in the brain. (J:172679)