GHRL and obesity due to melanocortin 4 receptor deficiency: Indeed, several studies have shown that inhibition of the ghrelin signalling pathway results in a reduction of food intake through decreased appetite and increased energy expenditure and fat catabolism, underlining the potential of ghrelin receptor antagonists, inverse agonist and other strategies targeting the ghrelin hormone in the development of anti-obesity therapeutics (for review see[7], [11]–[15]).