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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The Australasian Journal of Dermatology.

Enter the email address you signed up with and we’ll email you a reset link. Endocrinology and Metabolismvol. Field and laboratory design Duringfive samplings were carried out in four 1O-km2 areas, represen- tative of the four above defined habitats. This takes special relevance if we consider that for other rodents such as mice and rats, PRLR is a key component regulating ovarian function and governing the regulation of P4 secretion [ 22357 ].

The distribution of vizcacha includes savannas, Monte scrubby areas and arid shrubby areas Olrog and Lucerorarely located higher than m Llanos and Crespo cresp An unusual long gestation is also a distinctive trait of vizcachas.

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Scarcity of forbs could explain this low nutritional resources quality. Effect of pituitary and ovarian hormones on human melanocytes in vitro.

Credpo of the primary antibody did not reveal any staining in all examined sections. Chinchillidaeis a hystricognathe fossorial rodent that inhabits the Pampas region of Argentina extending up to the South of Paraguay and Bolivia [ 24 ]. For this purpose, four pineal glands per group were analyzed. A “cafeteria style” Goss-Custard allows the herbivores to evaluate the food quality through a continuous sampling, as an adaptation to unpredictable changes in phenology and nutritional vizcxcha of the vegetation determined by strong climatic fluctuations, usual in arid environments Hansen et al.

Dietary preferences The association between diet and plant availability was significant for all the microhabitats, except for Huayquerfas Coloradas rocky elevations Table 2vizcachz the significance levels were generally higher for plains than for rocky elevations.


The relief presents gentle slopes and large plains, interrupted by basaltic steps and groups of hills originated by the vol- canic activity Gonzalez Diaz 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.

Journal of the Anatomical Society of India. Poa and Panicum are strongly consumed by most herbivores in La Payunia Puig et at. Vizcacha’s feeding behaviour does not agree with the Optimal Foraging Theory OFTwhich predicts a higher selectivity in situations of higher food diversity and abundance. Probable local modulatory action of melatonin.

Important goals for future studies are to evaluate: Estradiol and progesterone serum levels were determined by RIA. Arroyuelo for their technical participation. Image of female pineal gland in late pregnancy. In order to eliminate any emission crosstalk between the fluorophores, sequential line scanning lambda strobing mode was used when acquiring the images. Three levels of significance were considered in the statistical results, expressed as: A high selectivity ocurred in habitats and sea- sons with low plant diversity.

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. Faecal samples composed by 10 fresh pellets were collected from 10 vizcacheras selected on each sampling area. However, the female viscacha pineal gland has been scarcely studied [ 30 ].

IUCN Red List of Threatened Species

This is the first attempt to relate PRL as well as its ovarian receptor to some key steroidogenic markers involved in the production of P4 during gestation of vizcachas. The brains were exposed, and the pineal gland was immediately removed and used for light and electron microscopy. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The biology of Hystricomorph rodents. On the origin and significance of neuromelanin. Please review our privacy policy.


Grasses proportion did not change seasonally in vizcacha diet, in spite of their lower availability in winter Fig. Revista Argentina de Producci6n Animal, 6: Evidences of forced selectivity in La Payunia are: Morphofunctional aspects of the mammalian pineal gland.

Conflicts of Interest The authors declare that there is no conflict of interests regarding the publication of this paper.

The experimental design was approved by the local ethics committee and was in agreement with the guidelines of the National Institute of Health NIH, USA for the use of experimental animals. However, in the present study, the pineal pigments were evident in female viscachas.

Vizcacha’s diet in La Payunia, within the most arid and elevated region of its distribution, showed a similar variety since half of the plant species present in the field were included. Such stimulation is mandatory for the final reduction of P4 blood levels preceding vizcafha [ 11 — 16 ]. Results were vizcavha in terms of rat LH standards using the following standards: Variations in the amount of pineal pigments related to serum hormone levels were found between pregnant and nonpregnant viscachas.

International Journal of Endocrinology

Melanin, a brownish-black pigment, is produced by the skin melanocytes which are derived from the neural crest and constitute the second most abundant cell in the epidermis [ 12 ].

However, the role of pigment in these nervous structures has not been clearly demonstrated.

Thus, the changes in the amount of pineal melanin seems to indicate a direct relationship between pigment content and gonadal hormone crwspo during pregnancy, when estradiol and progesterone levels remain elevated for a long time. Rocky elevations of La Payunia are the shelter bizcacha Lagidium viscacia. The blood was collected by cardiac puncture for the evaluation of serum hormone concentration. Melanin pigmentation in mammalian skin and its hormonal regulation.

Each field contained between 90 and cells. International Journal of Molecular Science.