Cytology of the anterior pituitary at different times of the year in normal and methallibure-treated male Columbian black-tailed deer (<i>Odocoileus hemionus columbianus</i>)

West, Nels O.; Nordan, H. C.

doi:10.1139/z76-228

Cited by 8 publications

(2 citation statements)

References 14 publications

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“…Quantitative studies have shown that the thyrotrophs generally constitute a small proportion of the PD cells, 4–6% (Childs et al, 1983) and 2.09% (Dada et al, 1984) in rat, 1.36% in bat (Anthony and Gustafson, 1984), 0.43% in mouse (Messier, 1965), 5% in voles (Clarke and Forsyth, 1964), and 1% in black‐tailed deer (West and Nordan, 1976). In viscacha, the values observed were between 2.39% and 1.16% (summer–early autumn and winter, respectively), showing a similar proportion to that reported for other species.…”

Section: Discussionmentioning

confidence: 99%

Immunohistochemical and Morphometric Study of Pituitary Pars Distalis Thyrotrophs of Male Viscacha (Lagostomus maximus maximus): Seasonal Variations and Effect of Melatonin and Castration

Filippa¹,

Mohamed²

2008

The Anatomical Record

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The physiology and behavior of viscacha vary along the year according to the modifications of environmental signals such as the photoperiod length, temperature, rainfall pattern, food composition, and social interactions. The pituitary pars distalis thyrotrophs (TSH cells) of male viscacha were immunohistochemically identified, and the morphometric parameters: percentage of immunopositive area (% IA), cell percentage in pars distalis (% PDC), number of cells per reference area (no. cells/RA), and major cellular and nuclear diameters were analyzed. Three different groups of adult male viscachas were used: (1) captured in their natural habitat during the year, (2) melatonin-administered, and (3) castrated. The thyrotrophs were localized in the ventromedial sector, mainly in the pars distalis cephalic extreme. They were oval or pyramidal in shape, and their immunostaining intensity was heterogeneous. The % IA, % PDC, and no. cells/RA exhibited a significant decrease in June-July (winter, gonadal regression period) in relation to February-March (summer-early autumn, reproductive period), and they were recovered in August-September (later winter-early spring, gonadal recovery period). No morphometric variations of TSH cells were observed in melatonin-treated animals, whereas a decrease of the % IA, % PDC, and no. cells/RA was observed in castrated animals in relation to the intact animals. Our results show TSH cell morphometric variations during the year in agreement with the animal's different physiological conditions during the reproductive cycle, and probably in response to the environmental signals changes. Melatonin does not have a direct effect on the TSH cells. However, castration modifies some thyrotroph morphometric parameters, reinforcing the hypothesis that androgens affect the cells activity.

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Section: Discussionmentioning

confidence: 99%

Immunohistochemical and Morphometric Study of Pituitary Pars Distalis Thyrotrophs of Male Viscacha (Lagostomus maximus maximus): Seasonal Variations and Effect of Melatonin and Castration

Filippa¹,

Mohamed²

2008

The Anatomical Record

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“…The volume fraction of these cells in adult male rats has been estimated at 5% (Childs, 1983) and the numerical density in adult female rats at 2.6% to 3.5% (Poole and Kornegay, 1982). Thyrotropes constitute 0.43% of the cells of the pars distalis in mice (Messier, 19651, 5% in voles (Clarke and Forsyth, 1964), and 1 to 2% in black-tailed deer (West and Nordan, 1976).…”

Section: Distribution and Abundance Of Thyrotropesmentioning

confidence: 99%

Seasonal variations in pituitary thyrotropes of the hibernating bat Myotis lucifugus lucifugus: An immunohistochemical study

Anthony

Gustafson

1984

Anat. Rec.

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Pituitary thyrotropes were identified throughout the year in the hibernating bat Myotis lucifugus lucifugus by means of light microscopic immunohistochemistry. These cells occupied a small proportion of the volume of the pars distalis (mean = 1.36% in males; mean = 1.52% in females) and exhibited a limited distribution pattern that was characteristic of all animals examined. Cells that were immunoreactive with an antiserum directed against the beta subunit of thyroid-stimulating hormone were most numerous in the median rostral and ventral regions; they were scarce or absent in the dorsal portion of the gland and in the extreme lateral wings. No significant seasonal variations were observed in this cell population in females. In males, however, immunoreactive thyrotropes occupied a significantly larger proportion of the pars distalis in June (following arousal from hibernation than at other times of year. No evidence of involution was observed in these anterior pituitary cells in either males or females during hibernation.

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Seasonal changes in prolactin and growth hormone cells in the hypophyses of white‐tailed deer (Odocoileus virginianus borealis) studied by light microscopic immunocytochemistry and radioimmunoassay

et al. 1980

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Numerous investigators have shown a relationship between basal serum prolactin (PRL) levels and photoperiod in domestic ungulates, and we have shown recently that a similar seasonal baseline serum PRL profile exists in both sexes of a captive but free-breeding population of white-tailed deer. In order to localize and describe the distribution and possible seasonal changes of PRL and growth hormone (GH) cells in the adenohypophyses of deer, we have used antisera raised against ovine PRL and bovine GH and the unlabeled antibody enzyme technique, in conjunction with point counting morphometry. In addition, we have measured seasonal changes in pituitary PRL concentrations in this same population, using a heterologous application of a recently developed homologous radioimmunoassay (RIA) for ovine PRL. Our results show that GH and PRL cells comprise two morphologically separate and immunologically distinct populations. Growth hormone cells were distributed evenly throughout the gland, except in the zona tuberalis, and males had a slightly greater volume density of immunoreactive GH than females; however, there were no differences between sexes in the average size of these cells, and little seasonal change was observed in these cell populations. In contrast to GH cells, the volume density of PRL cells, the size of PRL cells, and the pituitary concentration of RIA--measurable PRL all showed marked seasonal changes in deer of both sexes. These changes were well correlated with one another and with previously reported changes in basal serum levels (in these animals), in that they all reached zenith during midsummer, and nadir in midwinter. Our results demonstrate the necessity of reporting the time of year and latitude (to specify photoperiod) in studies concerning PRL cell physiology, particularly when dealing with any wild animal population.

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Cytology of the anterior pituitary at different times of the year in normal and methallibure-treated male Columbian black-tailed deer (Odocoileus hemionus columbianus)

Cited by 8 publications

References 14 publications

Immunohistochemical and Morphometric Study of Pituitary Pars Distalis Thyrotrophs of Male Viscacha (Lagostomus maximus maximus): Seasonal Variations and Effect of Melatonin and Castration

Immunohistochemical and Morphometric Study of Pituitary Pars Distalis Thyrotrophs of Male Viscacha (Lagostomus maximus maximus): Seasonal Variations and Effect of Melatonin and Castration

Seasonal variations in pituitary thyrotropes of the hibernating bat Myotis lucifugus lucifugus: An immunohistochemical study

Seasonal changes in prolactin and growth hormone cells in the hypophyses of white‐tailed deer (Odocoileus virginianus borealis) studied by light microscopic immunocytochemistry and radioimmunoassay

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