Uptake of free and liposome-entrapped insulin by rat intestinal sacs in vitro.
Entrapment of insulin within distearoylphosphatidylcholine and cholesterol liposomes can protect the hormone from degradation in an in vitro gut-sac system and can increase the quantity of immunoreactive insulin that reaches the serosal fluid 26-fold. 95% of the insulin that reaches the serosal fluid is present within relatively intact liposomes. However, the presence of hydrolytic agents, probably enzymes, within the serosal fluid of everted gut sacs makes it necessary to separate the liposomes from the serosal fluid, by centrifugation, prior to release of the entrapped insulin with Triton X-100. This procedure prevents hydrolysis of the released insulin which can then be measured by radioimmune assay.
D000818:Animals; D006868:Hydrolysis; D007328:Insulin / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D008081:Liposomes / Q000008:administration & dosage*; D008196:Lymph / Q000378:metabolism; D051381:Rats; D012704:Serous Membrane / Q000378:metabolism
D007328:Insulin; D008081:Liposomes