Regional distribution and molecular forms of rat islet amyloid polypeptide.
Using a highly sensitive and specific radioimmunoassay (RIA) for rat islet amyloid polypeptide (IAPP), we clarified regional distribution and molecular forms of rat IAPP. IAPP[1-37] and IAPP[19-37] were identified in normal rat pancreas by sequence analyses IAPP[19-37], accounting for 57% of IAPP-immunoreactivity in rat pancreas, is a major molecular form of rat IAPP moiety. In human, however, IAPP[1-37] is the major component, with IAPP[17-37] composing as little as 2-6% of IAPP-immunoreactivity in pancreas. This indicates that processing of IAPP in pancreas differs in species. A large amount of IAPP (328.5 +/- 25.0 pmol/g wet weight) was found in rat pancreas and the peptide was also detected in pyloric antrum of the stomach, duodenum, jejunum, ileum, and colon at 0.1-0.8% of the level of pancreas. It was not detected in central nervous system. The content of rat IAPP in pancreas fell to 54% of control after 4 day fasting. The distribution of IAPP suggests its possible endocrine or paracrine function in pancreas and gastrointestinal tract.
Asai
J
J
Department of Internal Medicine, Miyazaki Medical College, Japan.
Nakazato
M
M
Miyazato
M
M
Kangawa
K
K
Matsuo
H
H
Matsukura
S
S
D000682:Amyloid / Q000032:analysis* / Q000302:isolation & purification; D000818:Animals; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D004435:Eating; D005215:Fasting; D007106:Immune Sera; D007074:Immunoglobulin G; D058228:Islet Amyloid Polypeptide; D008297:Male; D010179:Pancreas / Q000032:analysis*; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains
D000682:Amyloid; D007106:Immune Sera; D007074:Immunoglobulin G; D058228:Islet Amyloid Polypeptide