Subcutaneous administration of ghrelin stimulates energy intake in healthy lean human volunteers

Background: The gastric hormone ghrelin appears a useful agent to stimulate food intake in people with anorexia of illness. The loss of ghrelin's acyl group renders it inactive, thus it has been thought that subcutaneous administration may be problematic. Objective: To investigate whether human subjects are sensitive to the effects of ghrelin administered by single subcutaneous injection. Study design: Randomized, double-blind, placebo-controlled trial. Subjects: Sixteen healthy lean volunteers (eight men and eight women). Protocol: Fasted subjects received subcutaneous injections of ghrelin (3.6 nmol/kg) or saline. After 30 min, a buffet breakfast was served. Results: Ghrelin injection increased energy intake by 27% (ghrelin 5076 +/- 691 kJ versus saline 4230 +/- 607 kJ, P = 0.04). Ghrelin appeared to enhance the perceived palatability of the food offered (palatability score: ghrelin 81.1 +/- 3.6 versus saline 70.0 +/- 4.4; P = 0.03). Conclusions: These results suggest that subcutaneous ghrelin is effective at stimulating energy intake and improving palatability and may be of direct use in the treatment of appetite loss.