title: Effects of thyroid status on NEI concentration in specific brain areas related to reproduction during the estrous cycle.
abstract: We previously showed that short-term hypo- and hyperthyroidism induce changes in neuropeptide glutamic-acid-isoleucine-amide (NEI) concentrations in discrete brain areas in male rats. To investigate the possible effects of hypo- and hyperthyroidism on NEI concentrations mainly in hypothalamic areas related to reproduction and behavior, female rats were sacrificed at different days of the estrous cycle. Circulating luteinizing hormone (LH), estradiol and progesterone concentrations were measured in control, hypothyroid (hypoT, treated with PTU during 7-9 days) and hyperthyroid (hyperT, l-T4 during 4-7 days) animals. Both treatments blunted the LH surge. Hypo- and hyperthyroidism increased estradiol concentrations during proestrus afternoon (P-PM), although hypoT rats showed lower values compared to control during proestrus morning (P-AM). Progesterone levels were higher in all groups at P-PM and in the hyperT during diestrus morning (D2). NEI concentrations were lower in hypoT rats during the estrous cycle except in estrus (E) in the peduncular part of the lateral hypothalamus (PLH). They were also reduced by both treatments in the perifornical part of the lateral hypothalamus (PeFLH) during P-PM. Hypothyroidism led to higher NEI concentrations during P-PM in the organum vasculosum of the lamina terminalis and anteroventral periventricular nucleus (OVLT+AVPV). The present results indicate that NEI concentration is regulated in a complex manner by hypo- and hyperthyroidism in the different areas studied, suggesting a correlation between NEI values and the variations of gonadal steroid levels during estrous cycle. These changes could be, in part, responsible for the alterations observed in the hypothalamic-pituitary-gonadal axis in these pathologies.
authors.affiliation: Laboratorio de Ciencias Fisiológicas, Cátedra de Bacteriología y Virología Médicas, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, CP 5000 Córdoba, Argentina; Sección de Desarrollo Cerebral Perinatal (SPBD), Instituto de Histología y Embriología Mendoza (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Parque General San Martín, CP 5500 Mendoza, Argentina. Electronic address: caro.ayala.arg@gmail.com.
authors.forename: Carolina
authors.initials: C
authors.lastname: Ayala
authors.forename: Gisela Erika
authors.initials: GE
authors.lastname: Pennacchio
authors.forename: Marta
authors.initials: M
authors.lastname: Soaje
authors.forename: Norma Beatriz
authors.initials: NB
authors.lastname: Carreño
authors.forename: Jakson Cioni
authors.initials: JC
authors.lastname: Bittencourt
authors.forename: Graciela Alma
authors.initials: GA
authors.lastname: Jahn
authors.forename: María Ester
authors.initials: ME
authors.lastname: Celis
authors.forename: Susana Ruth
authors.initials: SR
authors.lastname: Valdez
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D004958:Estradiol / Q000097:blood; D004971:Estrus; D005260:Female; D006980:Hyperthyroidism / Q000503:physiopathology*; D007037:Hypothyroidism / Q000503:physiopathology*; D007986:Luteinizing Hormone / Q000097:blood; D009842:Oligopeptides / Q000378:metabolism*; D011374:Progesterone / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012098:Reproduction; D013972:Thyrotropin / Q000097:blood
chemical_list: D009842:Oligopeptides; C522850:neuropeptide EI; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D013972:Thyrotropin
keywords: 125I-Tyr NEI; AVPV; D(2); D2; E; Estrous cycle; GnRH; HPG; HPT; Hyperthyroidism; Hypothalamus; Hypothyroidism; IHy; LH; ME; ME and arcuate nucleus; ME+Arc; MPA; NEI; Neuropeptide glutamic-acid-isoleucine-amide; Neuropeptide glutamic-acid-isoleucine-amide (NEI); OVLT; P; PLH; PP; PeFLH; Reproduction; T(3); THs; TRH; TSH; anteroventral periventricular nucleus; estrus; gonadotropin releasing hormone; hyperT; hyperthyroidism induction; hypoT; hypothalamic–pituitary–gonadal axis; hypothalamic–pituitary–thyroid axis; hypothyroidism induction; incerto-hypothalamic area; l-T(4); l-thyroxine; luteinizing hormone; medial preoptic area; median eminence; organum vasculosum of the lamina terminalis; peduncular part of the lateral hypothalamus; perifornical part of the lateral hypothalamus; posterior pituitary; ppMCH; pre-pro-melanin concentrating hormone; proestrus; second day of diestrus; thyroid hormones; thyrotropin; thyrotropin-releasing hormone; triiodothyronine; type 2 iodothyronine deiodinase; tyrosine radioiodinated NEI