Bacterial lipopolysaccharide shifts fasted plasma ghrelin to postprandial levels in rats.

Lipopolysaccharide (LPS) injected intraperitoneally (i.p.) is known to decrease food intake. Ghrelin is a peptide hormone produced by the stomach with a potent orexigenic effect and plasma levels that are inversely correlated with the fed state. We examined changes in plasma ghrelin levels 3 h after LPS (100 microg/kg, i.p.) in fasted rats with or without a 1 h re-feeding period. LPS injection decreased the fasting levels of ghrelin by 51+/-5% compared with preinjection values while i.p. vehicle did not modify ghrelin levels in fasted rats. LPS at this dose reduced fasting-induced food intake by 60% compared with the i.p. vehicle group. Re-feeding decreased plasma ghrelin levels by 58+/-3% compared with pre-feeding fasting values in i.p. vehicle group. These data provide the first evidence that LPS shifts fasting ghrelin levels to those observed postprandially.