Islets of Langerhans purified from the adult pig pancreas were evaluated for insulin secretion in response to glucose and arginine and inhibition of insulin secretion by exogenous insulin in vitro. Insulin output from freshly isolated islets in the presence of 50 and 400 mg/dl glucose was 2.0 ± 0.8 and 3.2 ± 1.6 ?U/islet/min respectively (p < 0.05). A sigmoidal increase of hormone secretion was observed at increasing glucose concentrations (from 50 to 800 mg/dl), the plateau being reached at 400 mg/dl glucose. In the presence of 10 mmol arginine, a significant potentiation of insulin output was observed at a glucose concentration of 400 mg/dl (2.8 ± 0.4 vs 5.1 ± 1.2 ?U/islet/min); when glucose concentration in the medium was 50 mg/dl, arginine had no effect on hormone release. The addition of 50, 300, or 1000 ?U/ml of exogenous porcine insulin to the incubation medium caused an inhibition of insulin release from isolated islets incubated at 400 mg/dl glucose concentration. These results support the use of porcine islets of Langerhans as a model for transplantation studies.
In vitro function of porcine islets of Langerhans
MARCHETTI, PIERO;MASIELLO, PELLEGRINO;
1989-01-01
Abstract
Islets of Langerhans purified from the adult pig pancreas were evaluated for insulin secretion in response to glucose and arginine and inhibition of insulin secretion by exogenous insulin in vitro. Insulin output from freshly isolated islets in the presence of 50 and 400 mg/dl glucose was 2.0 ± 0.8 and 3.2 ± 1.6 ?U/islet/min respectively (p < 0.05). A sigmoidal increase of hormone secretion was observed at increasing glucose concentrations (from 50 to 800 mg/dl), the plateau being reached at 400 mg/dl glucose. In the presence of 10 mmol arginine, a significant potentiation of insulin output was observed at a glucose concentration of 400 mg/dl (2.8 ± 0.4 vs 5.1 ± 1.2 ?U/islet/min); when glucose concentration in the medium was 50 mg/dl, arginine had no effect on hormone release. The addition of 50, 300, or 1000 ?U/ml of exogenous porcine insulin to the incubation medium caused an inhibition of insulin release from isolated islets incubated at 400 mg/dl glucose concentration. These results support the use of porcine islets of Langerhans as a model for transplantation studies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
