title: Specific enkephalin-degrading aminopeptidase activity in the HPT and HPO axes of rats with breast cancer induced by N-methyl nitrosourea.
abstract: State and function of breast depend on an endocrinological balance, the upsetting of which can be a factor favorable to the development of cancer. Enkephalins (ENK) have been considered as a particular form of adaptation to defense to the organism against neoplastic processes. However, ENK may modify the endocrine functions of glands such as the ovary or the thyroid through the hypothalamus-pituitary axis, acting direct or indirectly as endocrine, paracrine or autocrine stimulatory growth factors. The present work analyses enkephalin-degrading tyrosyl aminopeptidase (EDA) activity in the hypothalamus-pituitary-thyroid (HPT) and hypothalamus-pituitary-ovary (HPO) axes in a rat model of breast cancer induced by N-methyl-nitrosourea (NMU) to state the relationship between ENK levels modification through EDA activity at different neuroendocrine levels and breast cancer. Results obtained show a decrease in EDA activity in hypothalamus, anterior and posterior pituitary, thyroid and ovary, suggesting increased levels of ENK in all these locations. These ENK may induce breast cancer cell growth and progression not only at breast level, but also acting at several neuroendocrine levels such as the HPT and HPO axes, inducing an unbalance of several other hormones, which could also facilitate the progression of cancer as an undesirable concomitant effect.
authors.affiliation: Facultad de Ciencias Experimentales y de la Salud, Departamento de Ciencias de la Salud, Area de Fisiología, Universidad de Jaén, Campus Universitario Las Lagunillas, E-23071, Jaén, Spain.
authors.forename: María del Pilar
authors.initials: Mdel P
authors.lastname: Carrera
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Ramírez-Expósito
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Valenzuela
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: García
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Mayas
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Arias de Saavedra
authors.forename: Rafael
authors.initials: R
authors.lastname: Sánchez
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Pérez
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Martínez-Martos
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism*; D000818:Animals; D001943:Breast Neoplasms / Q000139:chemically induced* / Q000201:enzymology*; D004745:Enkephalins / Q000378:metabolism; D005260:Female; D007031:Hypothalamus / Q000187:drug effects / Q000201:enzymology*; D008770:Methylnitrosourea / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000187:drug effects / Q000201:enzymology*
chemical_list: D004745:Enkephalins; D008770:Methylnitrosourea; D000626:Aminopeptidases; C025579:enkephalin degrading enzyme