The Effect of Dipeptidyl Peptidase-4 Inhibition on GLP-1 Induced Insulin Secretion and Glucose Turnover During Mild Stable Hyperglycemia in Young and Old Normal Volunteers
The Effect of Dipeptidyl Peptidase-4 Inhibition on GLP-1 Induced Insulin Secretion and Glucose Turnover During Mild Stable Hyperglycemia in Young and Old Normal Volunteers
This research is being done to evaluate the effect of glucagon-like peptide-1 (GLP-1, a naturally occurring hormone) on insulin release and to examine whether there is extra insulin release when GLP-1 is not allowed to be rapidly inactivated.
The purpose of the present proposal is to 1) examine the role of dipeptidyl peptidase (DPP-4) inhibition on insulin release during a hyperglycemic clamp while GLP-1 is being infused and, 2) further elucidate the role of the metabolite of GLP-1, that is GLP-1 9-36 amide (GLP-1m). During stable and very reproducible elevated plasma glucose levels the effect of increased active incretin levels with DPP-4 inhibitors should result in increased plasma insulin levels. Therefore the aim of this protocol is to document whether plasma insulin levels are increased following GLP-1 infusion in the presence or absence of DPP-4 inhibitors. Additionally, the investigators have shown that some improvement in glucose homeostasis during GLP-1 administration is due in part to the metabolite of GLP-1, i.e. GLP-1 (9-36) amide (GLP-1m). Therefore, the investigators will also test the role of the latter by infusing GLP-1m when the volunteers are being treated with DPP-4 inhibitors.
Inclusion Criteria:
Hct level of at least 34% for women and 36% for men
Women of non-bearing potential and women of childbearing potential using adequate contraception
Serum creatine level of less than 1.7 mg/dl
Four groups:
Exclusion Criteria: