title: Identification by immunoblotting of somatostatin proforms in a rat pancreatic cell line.
abstract: The immunoblotting technique is applied to the analysis of "somatostatin" compounds secreted by R.I.N. T3 cells. We can confirm that two proforms of 15,300 +/- 750 and 29,000 +/- 1,100 Da accumulate in the extracellular medium. The unexpected form of 29 kDa, probably a dimeric form, disappears in reducing conditions. However, the 15 kDa peptide is characterized by several antibodies directed against either the intramolecular cycle of somatostatin-14 or the N-terminal extension of somatostatin-28. The 15 kDa form presents the same electrophoretic mobility in SDS-PAGE than the prosomatostatin isolated from a hypothalamic extract. Furthermore, this compound corresponds to the calculated mass of 10,388 Da deduced from the cDNA sequence. The detection of an immunoreactive 6 kDa peptide in the gel filtration fractions suggests an intermediate step in the prosomatostatin processing in these cells.
authors.affiliation: INSERM, U151 Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Lherisson
authors.forename: M
authors.initials: M
authors.lastname: Svoboda
authors.forename: L
authors.initials: L
authors.lastname: Pradayrol
authors.forename: A
authors.initials: A
authors.lastname: Estival
authors.forename: J
authors.initials: J
authors.lastname: Christophe
authors.forename: N
authors.initials: N
authors.lastname: Vaysse
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002460:Cell Line; D010179:Pancreas / Q000032:analysis*; D011498:Protein Precursors / Q000032:analysis*; D051381:Rats; D013004:Somatostatin / Q000032:analysis*
chemical_list: D011498:Protein Precursors; D013004:Somatostatin; C028456:prosomatostatin