The endogenous cannabinoids (endocannabinoids) are lipid molecules that may mediate retrograde signaling at central synapses and other forms of short-range neuronal communication. The monoglyceride 2-arachidonoylglycerol (2-AG) meets several criteria of an endocannabinoid substance: (i) it activates cannabinoid receptors; (ii) it is produced by neurons in an activity-dependent manner; and (iii) it is rapidly eliminated. 2-AG inactivation is only partially understood, but it may occur by transport into cells and enzymatic hydrolysis. Here we tested the hypothesis that monoglyceride lipase (MGL), a serine hydrolase that converts monoglycerides to fatty acid and glycerol, participates in 2-AG inactivation. We cloned MGL by homology from a rat brain cDNA library. Its cDNA sequence encoded for a 303-aa protein with a calculated molecular weight of 33,367 daltons. Northern blot and in situ hybridization analyses revealed that MGL mRNA is heterogeneously expressed in the rat brain, with highest levels in regions where CB1 cannabinoid receptors are also present (hippocampus, cortex, anterior thalamus, and cerebellum). Immunohistochemical studies in the hippocampus showed that MGL distribution has striking laminar specificity, suggesting a presynaptic localization of the enzyme. Adenovirus-mediated transfer of MGL cDNA into rat cortical neurons increased MGL expression and attenuated N-methyl-D-aspartate/carbachol-induced 2-AG accumulation in these cells. No such effect was observed on the accumulation of anandamide, another endocannabinoid lipid. The results suggest that hydrolysis by means of MGL is a primary mechanism for 2-AG inactivation in intact neurons

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Results of analytical studies on the composition of l0 selected margarines representative of consumeravailable hard and soft types are presented. Paired hard and soft products from the same manufacturer were chosen where possible. All of the margarines were compared on the basis of total fatty acid composition, polyunsaturated to saturated fatty acid ratios, total trans and the trans content of the monoene and diene fractions, location of the double bond in the monoene isomers, per cent conjugation, distribution of the fatty acids at the 2 position of the triglycerides, tocopherol content, and the ratios of c~-tocopherol to polyunsaturated fatty acids. As expected the soft margarines contained more polyunsaturated fatty acids than their companion hard types, but all soft margarines did not contain more polyunsaturated fatty acids than all of the hard margarines. The one margarine containing safflower oil had the highest polyunsaturated to saturated ratio. Eight of the ten margarines contained more than 15% trans monoene and nine contained less than 5% trans diene. Positional isomers in the monoene fraction were A6 to A12 with the cis A9 isomer predominating. All of the margarines contained less than 1.9% conjugation. The percentage of trans monoene at the 2 position was greater for some margarines than that in the total fatty acid. This was attributed to the preferential placement of polyunsaturated fatty acids at the 2 position in the original vegetable oils. The forms of tocopherol found were characteristic of the original vegetable oils. Ratios of a-tocopherol to PUFA varied from 0.1 to 0.5 mg/g. Determination of the relationship of the amount of tocopherol content to either source or hardness is not possible on the basis of our data.

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This paper gives analytical data on the composition of 14 selected consumer‐available liquid vegetable oils, including soybean, soybean‐cottonseed blends, corn, safflower, peanut, olive and apricot kernel oils. Label information identified six samples as specially processed or refined and three samples as cold pressed with no preservative added; the labels of the remaining five samples did not mention processing. Data are given for fatty acid composition,trans content, location of the double bonds in the unsaturated fatty acids, percent conjugation, tocopherol content, fatty acid composition of the 2‐poisition of the triglycerides, polyunsaturated to saturated fatty acid (P/S) ratio, and the ratio of α‐tocopherol to polyunsaturated fatty acids (α‐T/P). The ranges of values found were: conjugated unsaturation, 0.18–1.09%; α‐tocopherol, 0.01–0.60 mg/gm; total tocopherol 0.14–1.52 mg/gm; P/S, 0.5–8.7; and α‐TP, 0.03–2.26. The compositions of the fatty acids on the 2‐position and on the 1,3‐position of the triglycerides were compared with those calculated by the Evans’ hypothesis and found to agree well for all but olive and apricot kernel oils.

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The racemic triglycerides, glyceryl-1-palmitate-2,3-dibutyrate (PBB), glyceryl-1-butyrate-2,3-dipalmitate (PPB), glyceryl-2-butyrate-1,3-dipalmitate (PBP), and the diglyceride, racemic glyceryl-1-palmitate-3-butyrate (P-B) were synthesized and digested with pancreatic lipase. Each triglyceride was mixed with equimolar amounts of triolein (OOO) prior to incubation.The following order of digestion rates was observed: PBB>PPB>PBP>P-B. There was no evidence for short-chain fatty acid specificity; however the triglycerides containing butyric acid were hydrolyzed more rapidly than OOO. Based upon the fatty acid composition of partial glycerides, digestion of butyrate glycerides was not a simple phenomenon. For example, in the digestion of PBB, butyric acid accumulated faster than palmitic acid in the diglycerides, and monobutyrin was found to accumulate when the diglyceride, P-B, was digested. As evidenced by the fatty acid composition of the monoglycerides, positional specificity of pancreatic lipase was always maintained.

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