title: Production of immunoreactive atrial natriuretic polypeptide in neuroendocrine tumors.
abstract: BACKGROUND
  Peptide hormone synthesis in neuroendocrine tumors is a well-recognized phenomenon. However, production in neuroendocrine tumors of atrial natriuretic polypeptide (ANP), a newly discovered peptide hormone from the heart, has not been studied extensively.
  
  
  METHODS
  The presence of immunoreactive human ANP (IR-hANP) in neuroendocrine tumors was determined using a specific human ANP radioimmunoassay. Neuroendocrine tumors examined included 9 small cell carcinomas of the uterus, 28 small cell carcinomas of the lung, 20 carcinoid tumors, 54 pancreatic endocrine tumors, 17 neuroblastic tumors, 14 pheochromocytomas, and 14 medullary carcinomas of the thyroid. Twenty atrial tissues also were examined as the control. Molecular size of IR-hANP in the extracts of atrial and tumor tissues was determined by gel chromatography.
  
  
  RESULTS
  IR-hANP was detected in the extracts of small cell carcinoma of the uterus, small cell carcinoma of the lung, and carcinoid tumor, with concentrations ranging from 3.1 to 210 ng/g wet weight tissue. No IR-hANP was detected in the extracts of pancreatic endocrine tumor, neuroblastic tumor, pheochromocytoma, and medullary carcinoma of the thyroid. The frequency of production of IR-hANP in neuroendocrine tumors was highest in small cell carcinoma of the uterus (44%), followed by small cell carcinoma of the lung (18%) and carcinoid tumor (15%). IR-hANP present in the extracts of small cell carcinomas of the uterus had molecular size heterogeneity, with three fragments in addition to alpha-, beta- and gamma-human ANP.
  
  
  CONCLUSIONS
  These results indicate that IR-hANP is produced by neuroendocrine tumors and that the molecular size of IR-hANP in tumor tissues is different from that in atrial tissues.
authors.affiliation: Growth Factor Division, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yoshinaga
authors.forename: K
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Abe
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Mishima
mesh_terms: D009320:Atrial Natriuretic Factor / Q000096:biosynthesis* / Q000302:isolation & purification; D002276:Carcinoid Tumor / Q000378:metabolism; D018288:Carcinoma, Small Cell / Q000378:metabolism; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism; D018358:Neuroendocrine Tumors / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000378:metabolism; D010673:Pheochromocytoma / Q000378:metabolism; D011863:Radioimmunoassay; D013964:Thyroid Neoplasms / Q000378:metabolism; D014594:Uterine Neoplasms / Q000378:metabolism
chemical_list: D009320:Atrial Natriuretic Factor