Structure of ghrelin splice variants containing a putative signal peptide. For each splice variant the exon structure, the predicted protein structure and amino acid sequence is depicted. A putative signal peptide (SP) in exon -1 is indicated by bold letters in the amino acid sequence. Obestatin coding sequence is depicted in red font, while an exon 3-deleted proghrelin peptide is shown in blue font. The splice variant that may encode putative C-ghrelin [GenBank:EF549574] was also expressed in the heart and spleen. Obestatin mRNA variants were obtained from the human stomach [GenBank:EF549575], while a variant that may encode an exon 3-deleted (Δex3) proghrelin peptide [GenBank:EF549557] was found in the PC3 human prostate carcinoma cell line. A mRNA variant obtained from leukocytes with a 5' truncated exon 2 [GenBank:EU072086] may encode a C-ghrelin peptide missing a single glutamine residue at position 24 (des-Gln24-C-ghrelin, underlined in the C-ghrelin amino acid sequence).