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Effective portal insulin delivery with enzyme-protected capsules in pancreatectomized pigs

1992; Elsevier BV; Volume: 23; Issue: 1 Linguagem: Inglês

10.1016/0306-3623(92)90047-n

1879-0011

A.N. Elias, Iain J. Gordon, Nosratola D. Vaziri, G. Chune, M.R. Pandian, Grant Gwinup, Robert C. Wesley,

Pancreatitis Pathology and Treatment

1. Plasma concentrations of insulin, C-peptide, glucagon and glucose were measured in surgically pancreatectomized pigs given insulin into the colon directly and in enteric peptidase-resistant (methacrylic acid copolymer-encapsulated) form. 2. Following introduction of insulin-containing capsules, plasma insulin concentration rose from 2.7 ± 0.1 μU/ml to 110.9 ± 51.9 μU/ml in the portal vein, and from 2.6 ± 0.1 μU/ml to 26.9 ± 7.3 μU/ml in the systemic circulation. Corresponding portal and systemic values after direct (non-encapsulated) insulin instillation were 28.2 ± 15.9 μU/ml to 44.8 ± 13.0 μU/ml and 7.5 ± 2.6 μU/ml to 15.2 ± 2.5 μU/ml respectively. Insulin concentrations peaked at 75 min in the group as a whole and between 60–90 min in individual animals. Absorption was most pronounced in pigs given aprotinin (a trypsin inhibitor) with insulin. 3. Plasma portal vein glucose concentrations fell from 76.2 ± 8.9 mg/dl to 31.1 ± 3.2 mg/dl 150 min after encapsulated insulin administration. Corresponding systemic glucose levels were 84.5 ± 11.0 mg/dl and 37.0 ± 1.4 mg/dl. 4. Colonic administration of insulin in methacrylic acid coated capsules results in peak portal and systemic insulin levels 60–90 min after administration. Co-administration of aprotinin enhances the fraction of insulin absorbed.