AREGU December 46/6

Moore, Craig A., Jeffrey D. Kittilson, Melissa M. Ehrman, and MarkA. Sheridan. Rainbow trout (Oncorhynchus mykiss) possess two somatostatin mRNAs that are differentially expressed. Am. J. Physiol. 277 (Regulatory Integrative Comp. Physiol. 46): R1553–R1561, 1999.— Previously, we isolated a 624-bp cDNA encoding for a 115amino acid preprosomatostatin containing [Tyr7,Gly10]somatostatin (SS)-14 (now designated PPSS-II8) obtained from the endocrine pancreas (Brockmann bodies) of rainbow trout. In this study we have characterized a second cDNA obtained from trout pancreas that is 600-bp in length and encodes for a 111-amino acid precursor containing [Tyr7,Gly10]SS-14 (PPSS-II88). The nucleotide and amino acid identity between the two cDNAs is 82.3 and 80.5%, respectively. Both PPSS-II8 and PPSS-II88 mRNA were present in esophagus, pyloric ceca, stomach, upper and lower intestine, and pancreas, whereas only SS-II88 mRNA was present in brain. PPSS-II88 mRNA was more abundant than PPSS-II8 mRNA in pancreas, whereas PPSS-II8 mRNA was more abundant than PPSS-II88 mRNA in stomach. Fasting increased pancreatic PPSS-II88 mRNA levels but had no effect on the levels of PPSS-II8 mRNA. These results indicate the existence of two nonallelic pancreatic SS-II genes that are differentially expressed, both in terms of distribution among tissues and in terms of relative abundance within the tissues.