Lymphatic transport of stearic acid and its effect on cholesterol transport in rats.

Lymphatic transport of stearic acid, given as completely hydrogenated rapeseed oil (R10), 9 to 1 (R9) and 5 to 5 (R5) mixtures of R10, and soybean oil and completely hydrogenated tallow (T) was examined in the rat cannulated thoracic duct. R10, R9, R5, and T contained 91.4, 81.5, 46.5, and 63.6% stearic acid, respectively. A large portion of the remaining fatty acids in T was palmitic acid (31%). These fats were emulsified with bile salt and albumin, and administered via a stomach tube. Lymphatic recovery of stearic acid at 24 h was lowest in R10 and highest in R5, and intermediate in R9 and T. Recovery of oleic and linoleic acids in rats given R5 was almost complete and significantly higher than that of stearic acid. When T was given, the 24 h recovery of stearic acid was significantly lower than that of palmitic acid. A highly inverse correlation between the recovery and the content of stearic acid in administered fats was observed in R10, R9, and R5. Lymphatic recovery of cholesterol was almost parallel with that of stearic acid. Although the content of stearic acid in T was lower than that in R9, the recovery of stearic acid and cholesterol was almost similar. The results indicate that the rate of lymphatic recovery of stearic acid is affected by the quantity and quality of coexisting fatty acids.