Calcitonin mRNA is produced in liver by two different splicing pathways.
Calcitonin, the hypocalcemic hypophosphatemic hormone is produced in the thyroid by the C-cells. We recently detected the presence of calcitonin and its messenger in hepatic tissue in vivo and in vitro. The calcitonin precursor is composed of the N-terminal peptide, calcitonin and a carboxyterminal peptide. We previously reported that in normal human thyroid and in medullary thyroid carcinoma a second calcitonin messenger is expressed in low quantities. This mRNA differs in its 3' region from the first one. It also codes for the N-terminal peptide, calcitonin and a carboxyterminal peptide which differs by the last eight amino acids from the first. We report here that both calcitonin mRNAs are expressed in normal or tumoral liver. Direct estimation, by a specific immunoassay, of the levels of carboxyterminal peptide II, the specific peptide coded for by calcitonin mRNA II, confirmed that this peptide is synthesized in human liver.
Bracq
S
S
Unité 349 INSERM, Centre Viggo Petersen, Hôpital Lariboisière, Paris, France.
Taboulet
J
J
Machairas
M
M
Lasmoles
F
F
Houssin
D
D
Moukhtar
M S
MS
Jullienne
A
A
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D002116:Calcitonin / Q000096:biosynthesis* / Q000737:chemistry; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis*; D012016:Reference Values; D013964:Thyroid Neoplasms / Q000378:metabolism; D014407:Tumor Cells, Cultured
D010446:Peptide Fragments; D012333:RNA, Messenger; D002116:Calcitonin