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 high plant cover in the plains of Guadalosos, Huay- querfas Coloradas and Zaino, strongly dominated by grasses Fig. In order to establish the different groups, the time of capture was carefully planned according to the natural crepo cycle of the vizcachas previously described by Llanos and Crespo [ 33 ] and also based on our own field expertise [ 28 — 3234 — 36 ].

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. Four different large habitats used by vizcachas Huayquerias Coloradas, Zaino, Guadalosos and Escoriales were selected in order to analyze if the vizcacha diet changes vizxacha to differences in vizcachw availability among habitats.

International Journal of Endocrinology

Due to restricted light exposition, the viscacha constitutes an interesting model for studying the pineal gland and the processes in which it is involved. Animals were grouped according to their reproductive status as the following: Within the plains, Poa availability was significantly higher in Escoriales and lower in Huayquerfas Coloradas, while Zaino and Guadalosos showed the highest Pan i- cum availability Fig.

P4 production is tied to the expression level of these two enzymes. Molecular and Biomolecular Spectroscopy. In conclusion, we suggest that the pineal gland of female viscacha may be more susceptible to endocrine cues during pregnancy and less subject to the environmental photoperiod, as in the case of the male viscacha.

Comparative ultrastructural studies of the pineal gland of rodents. The reproductive physiology of the plains viscacha, Lagostomus maximus. Both fluorescent-coupled antibodies were purchased at Invitrogen Corp.


GAPDH was used as housekeeping gene. Photoreceptor-specific proteins in the mammalian pineal organ: During gestation, particularly from midpregnancy, we detected a significant accumulation of pituitary PRL that reached its maximum at term pregnancy.

The ultrastructure of the pigmented cells exhibited an ovoid or rounded nucleus in shape, with heterochromatin dispersed in the nuclear matrix. Spatial and seasonal differences in quality and quantity of food availability in La Payunia were useful to test this hypothe- sis. The CL expresses key proteins and steroidogenic enzymes involved in the uptake, synthesis, and transport of cholesterol and in the processing of cholesterol to P4. The association between diet and availability compared the ri and ni frequencies by using the Spearman’s two-tailed rank correlation coefficient rs’ Siegel The amount of melanin in relation to sex varies according to the species.

Since the first descriptions, this species was associated to prairies, and named” plains vizcacha” d’ Azara Field and laboratory design Duringfive samplings were carried out in four 1O-km2 areas, represen- tative of the four above defined habitats. Immunoreactivity is shown in black color modification of diaminobenzidine vzcacha by addition of nickel and is highlighted by arrows.

The relief presents gentle slopes and large plains, interrupted by basaltic steps and groups of hills originated by the vol- canic activity Gonzalez Diaz Sections were counterstained with hematoxylin for morphological xrespo, dehydrated, and mounted.

Grasses proportion did not change seasonally in vizcacha diet, in spite of their lower availability in winter Fig. This classification was established according to previous reports in our laboratory [ 32 — 34 ].

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. The presence of pigment has been demonstrated in different nervous structures such as crespp of retina, substantia nigraand locus coeruleus. The sections were examined using an Olympus BX light microscope. However, further studies are necessary to confirm this relationship. Premelanosomes and melanosomes were identified in pigmented cells, pinealocytes, and interstitial cells.

Animal Handling Twenty-five female vizcachas, L. The present paper is focused crezpo evaluate if these patterns are the same in an arid, elevated and heterogeneous envi- ronment, composed of a mosaic of rocky and plains microhabitats, where quality vizcachs quantity of food are scarce and unpredictable Puig et at.


In mice and rats, the corpora lutea are the main source of P4 that will support the gestation process. We detected PRLR immunoexpression throughout the entire gestation. An unusual long gestation is also a distinctive trait of vizcachas.

A higher predation risk may prevent vizcachas from using ccrespo and rocky ele- vations, where pumas take refuge. The highest densities were detected in Zaino and Huayquerias Coloradas The climate belongs to the continental desert type Consejo Federal de Inversiones Journal List Int J Endocrinol v. Probable local modulatory action of melatonin.

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. Both coarse grasses tended to be avoided, and the relevance of Stipa as the main complementary element in vizcacha’s diet should be attributed to its high availability rather than to its quality. Despite livestock might favour vizca- chas establishment, the fact that both herbivores share the use of grasses in the plains suggests not to discard an interspecific competition situation.

Abstract Prolactin PRL is essential for the maintenance of the corpora lutea and the production of progesterone P4 during gestation of mice and rats, which makes it a key factor for their successful reproduction. The South American plains vizcacha, Lagostomus maximus Rodentia: Suculents were not foraged.

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IUCN Red List of Threatened Species

Our analysis of LHR expression in the ovary of vizcachas revealed an active transcription level at midpregnancy and in response to the LH surge. The rate of PRL transcription increased along pregnancy as well. Several melanogenesis stages were observed Figure 6 a.

Melanin pigmentation in bovine pineal gland and its possible correlation with gonadal function. These slices were placed in a 0.