title: Does the conceptus of the viviparous lizard Barisia imbricata imbricata participates in the regulation of progesterone production and the control of luteolysis?
abstract: It is generally accepted that progesterone is necessary to maintain gestation; however, the mechanisms that control the production of this steroid remain unknown. The corpus luteum has been assigned a central role in the maintenance of gestation based on its capacity to produce progesterone. A pseudopregnancy model was performed in a viviparous lizard, Barisia imbricata imbricata, to determine whether the absence of embryos would affect the pattern of progesterone production or the corpus luteum histology. Blood samples were obtained prior to ovulation and at 8, 16, and 24 weeks after ovulation (pseudopregnant and pregnant lizards), as well as one day after parturition (pregnant lizards) or 32 weeks after ovulation (pseudopregnant lizards). The corpus luteum was surgically removed one day after blood samples were obtained. Blood aliquots from nongravid females were obtained at similar timepoints. We found a significant reduction in plasma progesterone concentrations at 24 and 32 weeks post-ovulation in pseudopregnant lizards compared with those observed at similar times in intact pregnant lizards, whereas the progesterone levels in non-gestant lizards remained significantly lower than in either pseudopregnant or pregnant lizards. Moreover, we observed that the histological appearance of the corpus luteum from pseudogestational females (obtained 24 and 32 weeks post-ovulation) differed from the corpora lutea from lizards in late gestation and intact parturient lizards. These observations suggest that the conceptus participates in the regulation of progesterone production in late gestation and also in luteolysis control.
authors: Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores, Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios no. 1, Los Reyes Iztacala A. P. 314, Tlalnepantla 54090, Estado de México CP, Mexico. Electronic address: martor@servidor.unam.mx.
authors: Martín
authors: M
authors: Martínez-Torres
authors: Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores, Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios no. 1, Los Reyes Iztacala A. P. 314, Tlalnepantla 54090, Estado de México CP, Mexico.
authors: Martha
authors: M
authors: Salcedo-Álvarez
authors: Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores, Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios no. 1, Los Reyes Iztacala A. P. 314, Tlalnepantla 54090, Estado de México CP, Mexico.
authors: Carmen
authors: C
authors: Alvarez-Rodríguez
authors: Laboratorio de Hormonas Proteicas, Departamento de Biología de la Reproducción, Instituto de Ciencias Médicas y de la Nutrición Salvador Subirán, México DF, Mexico.
authors: Mario
authors: M
authors: Cárdenas-León
authors: Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores, Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios no. 1, Los Reyes Iztacala A. P. 314, Tlalnepantla 54090, Estado de México CP, Mexico.
authors: Juana
authors: J
authors: Luis
authors: Laboratorio de Inmunidad en Mucosas-Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Los Reyes Iztacala AP 314, Tlalnepantla CP 54090, Estado de México, Mexico.
authors: Leticia
authors: L
authors: Moreno-Fierros
mesh_terms: D000818:Animals; D003338:Corpus Luteum / Q000166:cytology; D004625:Embryo, Nonmammalian / Q000502:physiology*; D005260:Female; D008116:Lizards / Q000502:physiology*; D003341:Luteolysis / Q000502:physiology*; D011374:Progesterone / Q000378:metabolism*; D052286:Viviparity, Nonmammalian / Q000502:physiology*
chemical_list: D011374:Progesterone
keywords: Corpus luteum; Lizards; Progesterone; Pseudopregnancy; Reptiles; Viviparity