application wo 88 02756 european application 0 329 295 and pct application no wo 94 04752 an example of a somatostatin agonists which contain n terminal chemical substitutions are the methods for synthesizing somatostatin agonists is well documented and are within the ability of a person of ordinary skill in the art synthesis of short amino acid sequences is well established in the peptide art for example synthesis of h d phe phe phe d trp lys thr phe thr nh 2 described above can be achieved by following the protocol set forth in example i of european patent application 0 395 417 a1 the synthesis of somatostatin agonists with a substituted n terminus can be achieved for example by following the protocol set forth in wo 88 02756 european patent application no 0 329 295 and pct publication no wo 94 04752 the human sstr 1 sstr 2 sstr 3 sstr 4 and sstr 5 cdna clones have been described sstr 1 and sstr 2 in yamada y et al proc natl acad sci usa 89 251 255 1992 sstr 3 in yamada et al mol endocrinol 6 2136 2142 1993 and sstr 4 and sstr 5 in yamada et al biochem biophys res commun 195 844 852 1993 and are also available from american type culture collection atcc rockville md atcc nos 79044 sstr 1 79046 sstr 2 and 79048 sstr 3 based on the restriction endonuclease maps the entire coding region of each sstr cdna may be excised by suitable restriction endonuclease digestion maniatis t et al molecular cloning u2014 a laboratory manual cshl 1982 restriction endonucleases are available from new england biolabs beverly mass this cdna fragment was inserted into the mammalian expression vector pcmv russell d et al.