 To determine the role of nutrient status on ghrelin regulation of insulin secretion. We hypothesize that ghrelin and glucagon-like peptide-1 GLP-1both are hormones made in the gut, have differential effects on β-cell function in the fed state. We will compare insulin secretion and glucose turnover during meal ingestion using a dual glucose tracer and mixed meal protocol in subjects receiving ghrelin or saline. We will also determine the role of ghrelin-stimulated GLP-1 levels in this process using the GLP-1 receptor GLP-1R antagonist Exendin9-39 Ex-9. 