Plains viscacha were established in the laboratory to Spanish by Llanos & Crespo (), and some details of reproduction were given. Llanos, A. and J. Crespo. Ecología de la vizcacha (Lagostomus maximus maximus Blainv.) en el nordeste de la provincia de Entre Ríos. Rev. Llanos, A. C. and J. A. Crespo. Ecología de la vizcacha (Lagostomus maximus maximus Blainv.) en el nordeste de la Provincia de Entre Ríos. Revista de.

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Moreover, PRLR colocalized with LHR as well, throughout the 3 analyzed pregnancy stages, being midpregnancy the stage depicting maximum expression of both receptors Vizcaca 5. So far, our attempts to determine circulating PRL levels either by RIA or by ELISA did not yield positive results probably due to a subject linked to the specificity of the antibodies used in both techniques.

A possible explanation of this decrement would be that, during lactation, the constant demand exerted by the litter through the stimulus of suckling may cause the newly synthesized hormone to be immediately poured into the circulatory system, preventing its accumulation into the lactotrophs.

On the origin and significance of neuromelanin. GAPDH was used as housekeeping gene. Under these conditions, the photoperiod and the retinal-pineal axis play an important role.

Sandy soils dominated by grasses characterized Guadalosos and Zaino, the latter with a more pronounced slope and a higher proportion of phanerophytic shrubs. The highest densities were detected in Zaino and Huayquerias Coloradas Adjacent slides were tested for each vizcachw 5 animals per experimental group.

UV radiation and the skin.

International Journal of Endocrinology

This study was supported by crespk Consejo Nacional de Investigaciones Cientificas y Tecnicas of Argentina through a research grant.

Slides of this material were analyzed by the microhistological method of Baumgartner and Martin ; 50 fields per sample unit at X microscope magnification were examined, using plant reference material from La Payunia stored in the Ruiz Leal Herbarium IADIZA, Argentinaand described by Puig et al. Regrettably, neither of these techniques proved to be successful for PRL serum determination in vizcachas.


Revista Chilena de Historia Natural, All captured vizcachas were evaluated Table 1.

The biological significance of this pigment in the gland has not been clearly determined. Dorfman1,2 and J. Dietary selectivity within each plant category was estimated using the index proposed by Feinsinger et al.

Discussion The morphology of the mammal pineal gland presents great variability [ 193839 ]. Midpregnant vizcachas exhibited high levels of transcription for PRLR as well, which could be indicative of a cross talk mechanism between these two hormones for a coordinated dialogue towards an accurate luteinization process in L.

Identification of melanin in the bovine pineal gland. Rocky elevations of La Payunia are the shelter of Lagidium viscacia. Crwspo and Biomolecular Spectroscopy.

IUCN Red List of Threatened Species

In our laboratory, morphological studies of the male viscacha pineal gland have been carried out [ 27 — 29 ]. Pituitary expression of PRL increased during pregnancy. Two different regions in the parenchyma were observed proximal region and distal region. This hypothesis could justify the high abundances of vizca- cheras obtained in Huayquerias Coloradas and Zaino, the habitats with the highest live- stock densities Puig et at.

Grasses proportion did not change seasonally in vizcacha diet, in spite of their lower availability in winter Fig. This enzyme also belongs to the family of oxidoreductases, and it has shown to play a significant role in luteolysis and parturition.

A study in the humid region of vizcacha’ s distribution is needed to evaluate whether dietary variety remains wide where food is not a limiting factor. Analysis of qPCR data showed a 4-fold rise when transitioning from early pregnancy to midpregnancy and a marked decline at the end of gestationper group Figure 2 a. Intra- and interassay coefficients of variation were 7.

Acknowledgments The authors wish to thank Mrs. A more intensive feeding in the plains is justified by their higher plant cover, grasses proportion, and Vzicacha and Poa availabilities. Bucher proposes that habitat modification by livestock grazing favours establishment of vizcachas.


Postnatal development of female sheep pineal gland under natural inhibitory photoperiods: Immunocytochemical demonstration of rod-opsin, S-antigen, and neuron-specific proteins in the human pineal gland.

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Di Giorgio2,3 V. Nevertheless, the embryonic processes might explain the presence of melanin. Zaino was the only habitat without fizcacha significant difference between availability and diet for these spe- cies Table 2. These slices were placed in a 0. Daily morphological variations in the viscacha Lagostomus maximus maximus retina.

Poa, a good forage even during the dormancy period, was selecti- vely searched for in winter beyond the surrounding denuded area of vizcacheras vizcacah in a semiarid grassland Giulietti and Jackson P4 exerts its action via the PR, a member of the nuclear receptor superfamily of transcription factors. Morphometric Analysis The pigmented cells were counted in pregnant and nonpregnant vizcachz. The inset shows the argentaffin reaction with greater detail.

All captured vizcachas were evaluated, and their P4 levels are depicted in Table 1.

Relative frequencies of occurrence of each plant species i were obtained from faecal samples to describe the diet rand from point-quadrat transects to describe the crepo bility in the environment n.

Mammals of the Neotropics. Such stimulation is mandatory for the final reduction of P4 blood levels preceding parturition [ 11 — 16 ]. It vizcachx been shown that the positive regulation of the expression of LHR during CL formation in conventional rodent models is modulated by PRL [ 49 — 51 ].