Abstract
For we aimed at establishing enteral administration route of cytokine recombinant interleukin-2 (rIL-2)to enhance its effects, absorption of rIL-2 through the large intestine was investigated in the rats. rIL-2 (5 × 105 units/rat) dissolved in distilled water and lipid-surfactant mixed micelles(MM), which is composed of linoleic acid and sodium-taurocholate, as an absorption promoter was administered into the large intestine from rectum. During 5 hours after administration of rIL-2, the blood and the lymph were periodically taken from the jugular vein and the thoracic duct, respectively, The serum and lymphatic concentrations of rIL-2 were both undetectable in rats receiving rIL-2 dissolved in distilled water. By contrast, in rats receiving rIL-2 dissolved in MM, the lymphatic concentration showed a high level, 52 units/ml, whereas the serum concentration remained under the detectable level. Thus, the increase in the lymphatic selectivity of rIL-2 is considered due to its macromolecular weight ranging about 15000. Based on these results, it may be concluded that rIL-2 with MM can be remarkably absorbed from the large intestine and specifically transferred into the lymphatic system.
