| Outcome Measures: |
Primary: Acute Insulin secretion, Acute (first phase) insulin response (AIRg) to glucose will be calculated as the mean incremental responses above baseline (average of -20 and -10 and 0 minutes) to the samples drawn at 2, 4, 6, 8 and 10 minutes of the hyperglycemic clamp., At baseline and after 4 weeks of study drug treatment | Secondary: Second phase insulin secretion, The mean incremental insulin levels between 60 to 90 minutes of hyperglycemic clamp, At baseline and after 4 weeks of study drug treatment|Beta cell glucose sensitivity, Beta cell glucose sensitivity will be calculated as increment of insulin secretion in 60-90 minutes of the clamp minus basal insulin divided by glucose change in the same period, At baseline and after 4 weeks of study drug treatment|Glucagon-like peptide -1 (GLP-1), GLP-1 secretion Area under the curve (0-270 minute during hyperglyemic- OGTT clamp study), At baseline and after 4 weeks of study drug treatment|Glucagon, Glucagon area under the curve (0-270 minute) during hyperglyemic- OGTT clamp, At baseline and after 4 weeks of study drug treatment|Incretin effect, Difference between the post prandial (100-270min) and preprandial (60-90min) C peptide response, At baseline and after 4 weeks of study drug treatment
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