National Center for Biotechnology Information NCBI NLM MEDLINE Molecular animals humans pubmed abstract nih national institutes of health national library of medicine research support non-u.s. gov't male amino acid sequence peptides / chemistry Rats Sprague-Dawley Receptors Molecular Sequence Data sequence homology amino acid cloning calcium / metabolism peptides / genetics ghrelin peptide hormones* g-protein-coupled* pmid:10604470 doi:10.1038/45230 m kojima h hosoda k kangawa acylation gastric mucosa / metabolism* growth hormone / metabolism* peptides / isolation & purification* peptides / metabolism pituitary gland / metabolism pituitary hormones / metabolism cell surface / metabolism serine / metabolism