Physiological Effect of Ghrelin on Body Systems

Figure 4

Transport of h-ghrelin, m-ghrelin, and des-m-ghrelin across the BBB of mice. Although octanoylated (bioactive) m-ghrelin crosses the mouse BBB predominantly in the brain-to-blood direction, passage for des-m-ghrelin was observed only in the blood-to-brain direction. H-ghrelin, which differs from m-ghrelin in two amino residues only, was transported in both directions in mice. The extent to which and the direction in which the ghrelin can cross the BBB are therefore influenced by at least two features of its primary structure, its posttranslationally added fatty acid side chain and its amino acid sequence.