Portal absorption of fatty acids in lymph- and portal vein-cannulated rats

Evidence for conservation of dietary lipid in the rat during lactation and the immediate period after removal of the litter. Decreased oxidation of oral [1-14C]triolein

“…To examine this question, [1 -14C]octanoate, a medium-chain fatty acid which is directly absorbed into the portal blood (Hyun et al, 1967) and is not esterified in rat tissues (Fritz, 1961) As expected, the reciprocal changes in the accumulation of 14C-labelled lipid from [1-14C]triolein in mammary gland and white adipose tissue of lactating rats and rats whose litters had been removed were accompanied by reciprocal alterations in the activity of lipoprotein lipase (Table 2). However, the increased accumulation of 14C-labelled lipid in brown adipose tissue on removal of litters for 48 h was not accompanied by a comparable increase in lipoprotein lipase activity (Table 2).…”

“…1). Evidence that the measured 14CO2 originated from triacylglycerols (chylomicrons or very-low-density lipoproteins) rather than non-esterified fatty acids directly transported into the portal blood from the intestinal epithelial cells (Hyun et al, 1967;McDonald et al, 1980) is the considerable decrease (87%) in 14CO2 production when triolein-loaded virgin rats were injected with Triton WR 1339, which prevents the removal of plasma triacylglycerol (Scanu, 1965) (results not shown).…”

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

“…On the other hand, in the absorption of medium chain triglycerides (MCT) (carbon chain length; C:6-10), MCT are hydrolyzed easier than LCT by a pancreatic lipase (VALDIVIESO and SCHWABE, 1965a, b;GREENBERGER et al, 1966) and then medium chain fatty acids are transported in unesterified form into the portal vein system rather than into the lymph as triglycerides (BLOOM et al, 1951;KIYASU et al, 1952;BORGSTROM, 1955;BLOMSTRAND, 1955;HASHIM et al, 1964;HYUN et al, 1967;KAYDEN and MEDICK, 1969). …”

Metabolic adaptations to dietary fat malabsorption in chylomicron-deficient mice

“…This absorption efficiency would be sufficient to account for the estimated non-DNL body fat accumulation (as discussed above). There have also been reports of significant amounts of portal absorption of long-chain fatty acids [18][19][20]. It is tempting to speculate that some chylomicron-independent fat absorption may also occur in humans and may partially explain the generally mild symptoms of fat malabsorption in humans with abetalipoproteinaemia [21].…”