DISTRIBUTION AMONG TISSUES OF INTRAVENOUSLY ADMINISTERED SUCROSE OCTAOLEATE

The distribution of [C-14]oleate label in rat tissues in the 6 hr after intravenous administration of sucrose octa-[C-14]oleate (7.5 mg; SuO8) was compared with that observed after administration of [C-14triolein. the [C-14]oleate label, whether injected as triolein emulsion, or as chylomicrons obtained from donor animals, rapidly cleared from the serum; only 10% or less remained in the serum 15 min after injection. Labeled SuO8 disappeared less rapidly from the serum; about one-third of the dose was present after 15 min, and after 120 min 14% remained. In the liver, there was an initial greater accumulation of fatty acid label when an emulsion of either triolein or SuO8 was given rather than the chylomicrons. The octaester continued to accumulate in the liver throughout the 6 hr of study, and 78% of the initial dose was present at that time. By contrast, although one-third of the triolein, as of SuO8, was found in the liver shortly after injection, levels subsequently decreased; at 6 hr, 12% of the label remained associated with that organ. A small portion, up to 8% of the acid label, whether administered as chylomicrons or as a triolein emulsion, was found in the epididymal fat pads. Smaller amounts, usually 1% or less, of the [C-14]oleate label were found in fat pads following the injection of labeled SuO8. In a separate study, the levels of acid label in the liver and spleen were monitored for 21 days following the intravenous administration of [C-14]SuO8. There was an initial accumulation of approximately half of the injected lipid label in the liver and one-quarter in the spleen. By day 21, the level in the liver had decreased to one-third of that administered, while the level in spleen remained at one-quarter.