Evidence for a precursor for TRH in the neonatal rat pancreas.
Immunoreactive TRH-OH is present at low concentrations in acid extracts from 2- days old rat pancreas. The sequential treatment of these extracts with trypsin and carboxypeptidase A is followed by a three- and ten-fold increase in TRH-OH IR respectively. The molecular weight of the protein that gives rise to TRH-OH after enzymatic treatment ranges between 30000 and 40000 daltons. The appearance of TRH-OH in the tryptic digest suggests that TRH-OH is the COOH-terminal sequence of this protein. These results are the first evidence that TRH biosynthesis occurs through a large molecule precursor. However, this is an indirect demonstration since TRH cannot be generated under these conditions due to the lack of enzymatic amidation activity.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D002268:Carboxypeptidases / Q000378:metabolism; D043422:Carboxypeptidases A; D008970:Molecular Weight; D010179:Pancreas / Q000032:analysis*; D011498:Protein Precursors / Q000032:analysis*; D011863:Radioimmunoassay; D051381:Rats; D013973:Thyrotropin-Releasing Hormone / Q000096:biosynthesis*; D014357:Trypsin / Q000378:metabolism
D011498:Protein Precursors; D013973:Thyrotropin-Releasing Hormone; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D014357:Trypsin