title: Insulin-regulated aminopeptidase/placental leucil Aminopeptidase (IRAP/P-lAP) and angiotensin IV-forming activities are modified in serum of rats with breast cancer induced by N-methyl-nitrosourea.
abstract: BACKGROUND
  In previous reports, changes in oxytocinase activity in human breast cancer tissue and in the serum of N-methyl-nitrosourea (NMU)-induced rat mammary tumors were described. Insulin-regulated aminopeptidase (IRAP) has been identified with oxytocinase and has also been referred to as placental leucine aminopeptidase (P-LAP).
  
  
  METHODS
  The IRAP/P-LAP activity in rat serum was assayed to analyze the putative role that IRAP/P-LAP may play in regulating mammary gland carcinogenesis induced by NMU. Furthermore, as it has been recently described that IRAP/P-LAP is the angiotensin IV (Ang IV) receptor AT4, the activities of Ang IV-forming aminopeptidase N (APN) and aminopeptidase B (APB) were also assayed.
  
  
  RESULTS
  Changes in serum IRAP/P-LAP and Ang IV-forming APB activities were found in rats with mammary tumors induced by NMU. Both activities were greatly increased, although the Ang IV-forming APN activity was not modified.
  
  
  CONCLUSIONS
  These changes in aminopeptidase activities may reflect the local functional status of their substrates, which can be selectively activated or inhibited in the affected tissue as a result of specific conditions brought about by the tumor. Thus, these enzymatic activities may be involved in the promotion and progression of breast cancer through oxytocin (OT), vasopressin (AVP) and/or renin-angiotensin system (RAS) misregulation.
authors.affiliation: Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Pilar Carrera
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Ramírez-Expósito
authors.forename: Basilio
authors.initials: B
authors.lastname: Dueñas
authors.forename: María
authors.initials: M
authors.lastname: Dolores Mayas
authors.forename: María
authors.initials: M
authors.lastname: Jesús García
authors.forename: Susana
authors.initials: S
authors.lastname: De la Chica
authors.forename: Pedro
authors.initials: P
authors.lastname: Cortés
authors.forename: María
authors.initials: M
authors.lastname: Ruíz-Sanjuan
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Martínez-Martos
mesh_terms: D000626:Aminopeptidases / Q000097:blood*; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000097:blood; D000818:Animals; D010122:Cystinyl Aminopeptidase / Q000097:blood*; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000097:blood / Q000139:chemically induced / Q000201:enzymology*; D008770:Methylnitrosourea; D051381:Rats; D017208:Rats, Wistar; D011945:Receptors, Angiotensin / Q000097:blood
chemical_list: C090830:AT4 receptor; D011945:Receptors, Angiotensin; D000804:Angiotensin II; C012877:angiotensin II, des-Asp(1)-des-Arg(2)-Ile(5)-; D008770:Methylnitrosourea; D000626:Aminopeptidases; D010122:Cystinyl Aminopeptidase; C105964:leucyl-cystinyl aminopeptidase; C019721:aminopeptidase B