Ghrelin and the enteroinsular axis in healthy men

Ghrelin, a potent stimulator of GH secretion, also acts as an orexigenic hormone. Plasma ghrelin levels rise before meals with postprandial reduction, suggesting that circulating levels of enteroinsular hormones might influence ghrelin secretion. The aim of this study was to evaluate the effects of ghrelin on enteroinsular hormones in healthy men. Three tests were performed on 3 different days in 6 healthy men: On the first day, saline was infused from 0-120 minutes followed by a ghrelin bolus (1 microg/kg) administration (Test 1); on the second experimental day, GHRH was administered at 0 min, and a ghrelin bolus was given at 120 min (Test 2); on the third experimental day, GHRP-6 was administered at 0 min, followed by a ghrelin bolus at 120 min (Test 3). Plasma glucose, insulin, proinsulin, C-Peptide Glucagone Like Peptide one (GLP-1) determined at 0, 15, 30, 60, 90, and 120 min of the test period. There was a significant increase in AUC glucose (526.41+/-22.91 mmol . ml(-1) . min vs. 566.37+/-15.64 mmol . ml(-1) . min; p