Abstract: Standard pancreatic islet isolation results in &bgr;-cell toxicity due to nitric oxide and/or streptozotocin-like molecules that are generated during the isolation process. This toxicity can be limited by the addition of compounds that work through the glucosamine pathway in islets and/or by the addition of nitric oxide inhibitors. Unless prevented, this toxicity results in &bgr;-cells being unable to properly respond to high glucose, glucosamine, N-acetylglucosamine, or streptozotocin by increasing their relative amount of O-glycosylated protein. Likewise, in order to assess islet viability or the effect of diabetes drugs on &bgr;-cell function, islets that have been adequately protected during their isolation can be stimulated with low glucose, high glucose, glucosamine, N-acetylglucosamine, or streptozotocin with or without the drug(s) of interest present.