The effect of chain length on the activation and subsequent incorporation of fatty acids into glycerides by the small intestinal mucosa

An Electron Microscope Study of the Intestinal Absorption of Medium Chain and Long Chain Triglycerides in the Rat

“…In the present study, small particles within the agranular endoplasmic reticulum and the Golgi vacuoles during MCT absorption may represent the resynthesized triglyceride which is known to occur from biochemical investigation (GELB and KESSLER, 1963;SENIOR and ISSELBACHER, 1963;PLAYOUST and ISSELBACHER, 1964;GREENBERGER et al, 1965GREENBERGER et al, , 1966BRINDLEY and HUBSCHER, 1966;HYUN et al, 1967), although these particles observed in the Golgi vacuoles in fasted and MCT-fed rats are strikingly smaller in diameter than a chylomicron in the rat fed with LCT. From the view point of dimension, however, they come under the category of chylomicron (SCANU and BITTER, 1973).…”

“…These studies, together with the biochemical investigations (SENIOR andISSELBACHER, 1960 andDAWSON and ISSELBACHER, 1960;SJOSTRAND and BORGSTROM, 1967), have demonstrated that the endoplasmic reticulum in the absorptive cells is the site of triglyceride 153 resynthesis and both the Golgi complex and the endoplasmic reticulum are involved in the intracellular transport of LCT. Medium chain fatty acids, however, are known to be hardly resynthesized to triglyceride in the intestinal absorptive cells (DAWSON and ISSELBACHER, 1960;GELB and KESSLER, 1963;GREENBERGER et al, 1965 and1966;BRINDLEY and HUBSCHER, 1966). Since there seem to be only a few papers dealing with the morphological aspect of MCT absorption (MCKAY et al, 1967), very little is known about the detailed ultrastructural aspect of MCT absorption in the intestine.…”

Identification of Acyl Coenzyme A:Monoacylglycerol Acyltransferase 3, an Intestinal Specific Enzyme Implicated in Dietary Fat Absorption

“…In the intestine, the major digestive products of TAG produced by pancreatic lipase are 2-MAG (4) and the long chain fatty acids palmitate and oleate (5,9). Hence the superior MGAT3 substrate selectivity for these types of fatty acids and its high level of expression in the small intestine would allow it to fulfill the physiological function of synthesizing TAG from the large quantities of free fatty acids and 2-monoacylglycerol absorbed in the intestine.…”

The absorption of fat

“…One of these, the socalled alpha glycerophosphate pathway, is present in most cells capable of synthesizing triglyceride. Alpha glycerophosphate is acylated by fatty acids activated with CoA (Brindley and Hubscher, 1966) to form phosphatidic acid which is then dephosphorylated to form diglyceride which is further acylated to form triglyceride. But in addition there is a specialized mechanism whereby monoglyceride can be directly acylated with acyl-CoA derivatives thus preventing the need to break down the remaining original glyceride bonds and expend energy on resynthesizing them (Clark and Hubscher, 1961;Senior and Isselbacher, 1962).…”