Effect of insulin antibodies on pancreatic islet insulin and beta cell granule content

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Abstract
Normal rats injected intravenously with anti‐insulin guinea pig serum (AIS‐GP) exhibited a marked hyperglycemia which reached a maximum (>300 mg per 100 ml) at the third hour. The blood sugar was 172 mg per 100 ml by the eighth hour and was normal (100 mg per 100 ml) at 24 hours. Control animals injected with equal quantities of normal guinea pig serum did not show significant changes in blood sugar.In pancreatic tissue obtained from rats three hours after injection of AIS‐GP the aldehyde‐fuchsin staining granules of the beta cells were significantly fewer than in the controls. Quantitation studies indicated that in the AIS‐GP injected animals 26% of the islet volume was composed of 4+ and 3+ granulated beta cells as compared to 68% for rats injected with normal guinea pig serum. The cell granulation was normal 24 hours after injection of AIS‐GP. Electron microscopic studies confirmed that this decrease in aldehyde‐fuchsin staining was due to degranulation.The insulin content of microdissected islets obtained three hours after injection of AIS‐GP was significantly lower than that of the controls. The mean value (immunoassay determinations) for the AIS‐GP injected animals (89±30 units per gm dry weight of islet) was 38% that of the controls (232±66).