Circulating preprandial ghrelin to obestatin ratio is increased in human obesity

Context: Obestatin, a sibling of ghrelin derived from preproghrelin, opposes ghrelin's effects on food intake. Plasma obestatin profiles in relation to ghrelin have not been fully investigated in human obesity. Objective: We hypothesize that obesity might present with imbalance of circulating ghrelin and obestatin levels. Participants and Setting: Sixteen obese ( eight men, aged 58.8 +/- 4.9 yr; eight women, aged 59.9 +/- 9.6 yr) and 14 normal-weight individuals ( seven men, aged 52.7 +/- 5.9 yr; seven women, aged 56.1 +/- 4.9 yr) were evaluated at the in-patient department of Changhai Hospital, Shanghai, China. Main Outcome Measures: Total plasma ghrelin and obestatin levels, 1 h before and 2 h after breakfast, were measured by RIA. Results: Both preprandial plasma ghrelin levels ( P < 0.01) and obestatin levels ( P < 0.01) were lower in the obese compared with normal-weight controls. However, unexpectedly, the ratio of preprandial ghrelin to obestatin was higher in obese compared with normal-weight controls ( P < 0.01) even after adjustment for gender and age ( P < 0.01). The ratio of postprandial ghrelin to obestatin was decreased both in obese ( P < 0.05) and controls ( P < 0.01) compared with their preprandial levels. There were no significant differences in the ratio of postprandial ghrelin to obestatin between obese and normal-weight controls. Body mass index was positively correlated with and was a significantly independent determinant of the preprandial ghrelin to obestatin ratio. Conclusion: Circulating preprandial ghrelin to obestatin ratio is elevated in human obesity. We suggest that high preprandial ghrelin to obestatin ratio may be involved in the etiology and pathophysiology of obesity.