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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Such stimulation is mandatory for the final reduction of P4 blood levels preceding parturition [ 11 — 16 ]. Poa, a good forage even during the dormancy period, was selecti- vely searched for in winter beyond the surrounding denuded area of vizcacheras also in a semiarid grassland Giulietti and Jackson Forbs availability, strongly related to dietary quality Branch et ai.

A cresp procedure for lead staining of thin sections. Subscribe to Table of Contents Alerts. The scarse plant cover and the high phane- rophytes availability distinguished rocky elevations of Escoriales from the other microhabitats. In our laboratory, the morphology of the viscacha retinal melanosomes has been described [ 44 ]. Conflicts vuzcacha Interest The authors declare that there is no conflict of interests regarding the publication of this paper.

Pooled pituitary homogenates of high LH levels were serially diluted to prepare a standard curve for the vizcachas, and vizcadha parallelism with the rat standard curve was confirmed, as previously described [ 28 ].

Gestational stage was estimated by the time of capture and confirmed vizcqcha the surgical procedure by the degree of fetal development as previously described [ 3237 ]. Ultrastructure of the pineal body of the common vampire bat, Desmodus rotundus. Omission of the primary antibody did not reveal any staining in all examined sections. Effect of the photoperiod and administration of melatonin on folliculostellate cells cespo the pituitary pars distalis of adult male viscacha Lagostomus maximus maximus Vizcacna Histochemica.

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The significant differences were determined by Kruskal-Wallis test. The arrowhead indicates a well-developed Golgi complex in the pigmented cell. During lactation, pituitary PRL immunoexpression decreased to values similar to the basal production measured in non-ovulating non-pregnant animals Figure 6.

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Since the ovaries of the nonpregnant groups of this study LCT and NP exhibited almost the total absence of corpora lutea, the luteal immunoreactivity was analyzed only at the stages of pregnancy. Specificity of primary antibodies was corroborated in adjacent sections by omission of the primary antibodies.

Nevertheless, the embryonic processes might explain the presence drespo melanin. The American Journal of Anatomy. The corpus luteum CL is a cgespo endocrine gland that biosynthesizes steroids under the control of luteotropic factors. Table of Contents Alerts. This variety might be a conse- quence of food scarcity and unpredictability in the arid zones, rather than dietary gene- ralism.

The distribution of vizcacha includes savannas, Monte scrubby areas and arid shrubby areas Olrog and Lucerorarely located higher than m Llanos and Crespo Grasses could be important for vizcachas, because they provide dietary fibers essential for hindgut fermentation Branch et ai. Indexed in Science Citation Index Expanded. In relation with this hypothesis, we suggest that vizcachas tend to display a higher selectivity in circumstances in which preferred species are more available; this could be interpreted as food quality becoming a less limiting resource.

Biological Series of the Organization of American States, pp. Yet, we measured a marked decrease of PRL immunoreactivity in pituitary of lactating compared to term-pregnant females. This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

International Journal of Endocrinology

Morphological and morphometric changes of pituitary lactotrophs of viscacha Lagostomus maximus maximus in relation to reproductive cycle, age, and sex. Both fluorescent-coupled antibodies were purchased at Invitrogen Corp.

This clearly establishes the critical role of PRL in the maintenance of the CL and production of Vizczcha for rodent reproduction [ 232223 ] for a review.


Effect of pituitary and ovarian hormones on human melanocytes in vitro. In contrast, the pigmented cells number varied significantly according to sex in viscacha. Annales d’ Agronomie, Its best-known function is to protect the skin against the harmful effects of the ultraviolet radiation [ 3 — 5 ]. Immunoreactivity is shown in black color modification of diaminobenzidine precipitation by addition of nickel and is highlighted by arrows. Therefore, the Selective Quality Hypothesis may be applied to vizcachas expressed as: Unlike these rodents and the vast majority of mammals, female vizcachas Lagostomus maximus have a peculiar reproductive biology characterized by an ovulatory event during pregnancy that generates secondary corpora lutea with a consequent increment of the circulating P4.

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. Consumption of chamae- phytes was higher in Escoriales, whose plains differed from the others due to the high chamaephytes availability.

The hydrogen peroxide treatment was also carried out. More studies about herbi- vores dietary overlap, and their capability of habitat modification are needed in Nor- thern Patagonia.

A strong argentaffin reaction is exhibited in pigmented cells arrowheads and in extracellular space. Finally, the slides were dehydrated, cleared in xylene, and mounted using a synthetic mounting medium. Spatial and seasonal differences in cresppo and quantity of food availability in La Payunia were useful to crdspo this hypothe- sis.

We detected LHR-positive reactivity in luteal cells along the three stages of pregnancy. This classification was established according to previous reports in our laboratory [ 32 — 34 ].

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