Title: Failure of fasting to influence the GIP response to oral glucose in non-obese human subjects
Abstract: The plasma GIP response to an oral 50 g glucose tolerance test has been compared in eight non-obese human subjects after 12 and 36 h of fasting. Basal plasma GIP and basal plasma insulin concentrations were similar after 12 and 36 h of fasting. Basal blood glucose was lower after 36 h fasting than after 12 h fasting (P<0.0125). After 36 h fasting the oral glucose tolerance test stimulated higher blood glucose concentrations at 60, 90 and 120 min (p<0.0125) and higher plasma insulin concentrations at similar time points (p<0.05), but stimulated plasma GIP concentrations were similar after 12 and 36 h fasts. These findings show that the increased insulinotrophic effect of oral glucose after 36 h fasting in nonobese subjects is not due to an associated augmentation of the glucose-induced GIP response.