POLYGENIC EXPRESSION OF SOMATOSTATIN IN LAMPREY

Previous studies have led to the identification of three biosynthetica lly related molecular forms of somatostatin (somatostatin-14, -34 and -37) from the pancreas of the sea lamprey (Petromyzon marinus). We hav e now isolated from the brain of the same species a second form of som atostatin-14 that is identical to mammalian somatostatin-14 and differ s from lamprey pancreatic somatostatin-14 by the substitution Ser(12) to Thr. Larger forms of somatostatin were not identified in lamprey br ain in this study. These data suggest that the two molecular forms of lamprey somatostatin-14 are the products of different genes that are e xpressed in a tissue-specific manner.