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Metabolism of sn ‐1(3)‐Monoacylglycerol and sn ‐2‐Monoacylglycerol in Caecal Enterocytes and Hepatocytes of Brown Trout ( Salmo trutta )
Author(s) -
Li Keshuai,
Olsen Rolf Erik
Publication year - 2017
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-016-4215-0
Subject(s) - monoacylglycerol lipase , metabolism , biochemistry , salmo , triolein , glycerol , glyceride , chemistry , fatty acid , brown trout , biology , lipase , enzyme , endocannabinoid system , receptor , fishery , fish <actinopterygii>
sn ‐2‐Monoacylglycerol (2‐MAG) and sn ‐1(3)‐monoacylglycerol [1(3)‐MAG] are important but yet little studied intermediates in lipid metabolism. The current study compared the metabolic fate of 2‐MAG and 1(3)‐MAG in isolated caecal enterocytes and hepatocytes of brown trout ( Salmo trutta ). 1(3)‐Oleoyl [9,10‐3H(N)]‐glycerol and 2‐Oleoyl [9,10‐3H(N)]‐glycerol were prepared by pancreatic lipase digestion of triolein [9,10‐3H(N)]. The 1(3)‐MAG and 2‐MAG were efficiently absorbed by enterocytes and hepatocytes at similar rates. The 2‐MAG was quickly resynthesized into TAG through the monoacylglycerol acyltransferase (EC: 2.3.1.22, MGAT) pathway in both tissues, whereas 1(3)‐MAG was processed into TAG and phospholipids at a much slower rate, suggesting 2‐MAG was the preferred substrates for MGAT. Further analysis showed that 1(3)‐MAG was synthesized into 1,3‐DAG, but there were no accumulation of 1,3‐DAG in either enterocytes or hepatocytes, which contrasts that of mammalian studies. Some of the 1(3)‐MAG may be acylated to 1,2(2,3)‐DAG and then utilized for TAG synthesis. Alternatively, 1(3)‐MAG can be hydrolyzed to free fatty acid and glycerol, and re‐synthesized into TAG through the glycerol‐3‐phosphate (Gro‐3‐P) pathway. The overall data suggested that the limiting step of the intracellular 1(3)‐MAG metabolism is the conversion of 1(3)‐MAG itself.