This dose response study is proposed to explore the extent to which Nexium increases endogenous gastrin concentrations and to assess whether Nexium treatment may be useful in the setting of islet cell transplantation for type 1 diabetes to expand islet cells in vivo after transplant.

Islet transplantation has been shown to effectively treat type 1 diabetes by stabilizing blood glucose control while reducing/eliminating the need for exogenous insulin injections. However, for reasons still not fully understood, islet graft function tends to decline with time after transplant. Gastrin has been identified as a growth factor capable of stimulating islet cell expansion. Proton pump inhibitors are known to increase endogenous gastrin concentrations. This dose response study is proposed to explore the extent to which Nexium increases endogenous gastrin concentrations in healthy volunteers and to assess whether Nexium treatment may be useful in expanding islet cells in patients with type 1 diabetes. Three Nexium dose levels will be tested to determine the optimal dose for increasing plasma gastrin levels. The effect of Nexium on plasma concentrations of glucose, insulin, c-peptide, glucagon, and somatostatin will also be monitored.

Inclusion Criteria:

• age 18-65
• healthy
• free of clinical signs of diabetes, peptic ulcer, liver or kidney disease,autoimmune disease, or any acute chronic infection.

Exclusion Criteria:

• history or clinical signs of diabetes
• history of liver or kidney disease
• positive H-pylori status
• currently using a proton pump inhibitor
• prior hypersensitivity to Nexium
• pregnant or breastfeeding women