Recruitment, Dispersal, and Group Fusion in a Declining Population of the Plains Vizcacha (Lagostomus maximus; Chinchillidae)

Branch, Lyn C.; Villarreal, Diego; Fowler, Gene S.

doi:10.2307/1381901

Cited by 43 publications

(44 citation statements)

References 17 publications

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“…The animals with a body weight lower than 5 kg were carefully classified into immature (1-2 kg) and prepubertal (3-4 kg) according to body weight and light microscopy observations of testis [Llanos and Crespo, 1954;Branch et al, 1993;Mohamed et al, 2000;Filippa and Mohamed, 2006].…”

Section: Experimental Animalsmentioning

confidence: 99%

Immunohistochemical Study of Somatotrophs in Pituitary Pars Distalis of Male Viscacha (Lagostomus maximus maximus) in Relation to the Gonadal Activity

Filippa¹,

Mohamed²

2006

Cells Tissues Organs

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Somatotrophs were identified and quantified in pituitary pars distalis of male viscachas (Lagostomus maximus maximus) during the annual reproductive cycle, after the administration of melatonin, after castration and in different growth stages by immunohistochemistry and morphometric analysis. In adult male viscachas, the somatotrophs were distributed throughout the pars distalis during the reproductive cycle. They were oval, pyramidal or round in shape with a large round nucleus. The percentage immunopositive area, the major cellular diameter and the number of cells decreased during the gonadal regression period in relation to the values found in the reproductive period. The administration of melatonin did not provoke any variations of the morphometric parameters studied. On the contrary, a significant decrease in the percentage immunopositive area, in the major cellular diameter and in the number of somatotrophs in castrated viscachas was observed. The study of different growth stages showed that these morphometric parameters increased from immature to adult animals in the reproductive period. The results obtained suggested that the variations of the morphometric parameters of somatotrophs are more related to the gonadal development and activity than to a direct effect of melatonin.

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Section: Experimental Animalsmentioning

confidence: 99%

Immunohistochemical Study of Somatotrophs in Pituitary Pars Distalis of Male Viscacha (Lagostomus maximus maximus) in Relation to the Gonadal Activity

Filippa¹,

Mohamed²

2006

Cells Tissues Organs

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“…Loss of individuals from the trap population due to emigration cannot be distinguished from loss due to simple avoidance of traps [Branch et al, 1993] nor loss due to predation or other causes of death. Since predation on mouse lemurs is high [Goodman et al, 1993], this factor certainly accounts for the lack of recapture of some individuals.…”

Section: Population Compositionmentioning

confidence: 99%

Spatial distribution and population composition of the brown mouse lemur (Microcebus rufus) in Ranomafana National Park, Madagascar, and its implications for social organization

Atsalis

2000

Am. J. Primatol.

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“…In this research, 16 female viscachas (12 pregnant and 4 nonpregnant) were used. The age and reproductive condition of viscachas were carefully assessed on the bases of: (1) body weight [Llanos and Crespo, 1954;Branch et al, 1993] and (2) sexual maturity estimated by ovary histological analysis. Additionally, the uterine horns were examined to evaluate the presence of embryos and fetuses.…”

Section: Experimental Designmentioning

confidence: 99%

Interstitial Cells in the Pineal Gland of Pregnant and Nonpregnant Viscachas (Lagostomus maximus maximus): A Morphometric and Biochemical Study

Busolini

Gallol

Rodríguez

et al. 2018

Cells Tissues Organs

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The pineal gland of mammals undergoes morphological and biochemical changes throughout the gestation period. In viscachas, a seasonal breeding rodent, pregnancy lasts approximately 154 days and 3 stages can be defined, i.e., early, mid, and late pregnancy. The purpose of this study is to analyze morphometric variations in the expression of S-100 protein, glial fibrillary acidic protein (GFAP), and vimentin in the interstitial cells (IC) in pregnant and nonpregnant viscachas by immunohistochemistry (IHC). We also aim to evaluate a probable relation between glandular activity and pregnancy. The immunopositive percentage area (%IA) for the studied proteins and the number of immunoreactive cells against the S-100 protein with a visible nucleus (nº IC-S-100) were analyzed. Estradiol and progesterone serum levels were also determined by RIA. Variations in the expression of the S-100 protein and GFAP, as well as changes in the nº IC-S-100 related to serum hormone levels, were found between pregnant and nonpregnant viscachas. Viscachas in mid pregnancy exhibited the highest values of %IA for the analyzed proteins, followed by females in late and early pregnancy, while the nonpregnant ones showed the lowest values for all of the groups studied. Likewise, the nº IC-S-100 also varied following the same pattern. Thus, these variations seem to indicate a direct relationship between glandular activity and gonadal hormone levels. On these grounds, we may conclude that IC undergo changes in relation to ovarian hormone levels and participate in the regulation of glandular activity during pregnancy. However, further research is necessary to elucidate this relationship.

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Recruitment, Dispersal, and Group Fusion in a Declining Population of the Plains Vizcacha (Lagostomus maximus; Chinchillidae)

Cited by 43 publications

References 17 publications

Immunohistochemical Study of Somatotrophs in Pituitary Pars Distalis of Male Viscacha <i>(Lagostomus maximus maximus)</i> in Relation to the Gonadal Activity

Immunohistochemical Study of Somatotrophs in Pituitary Pars Distalis of Male Viscacha <i>(Lagostomus maximus maximus)</i> in Relation to the Gonadal Activity

Spatial distribution and population composition of the brown mouse lemur (Microcebus rufus) in Ranomafana National Park, Madagascar, and its implications for social organization

Interstitial Cells in the Pineal Gland of Pregnant and Nonpregnant Viscachas <b><i>(Lagostomus maximus maximus)</i></b>: A Morphometric and Biochemical Study

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