Pars tuberalis specific cells within the pars distalis of the adenohypophysis. An ontogenetic study

Rudolf, Thomas; Filler, Timm J.; Wittkowski, W.

doi:10.1016/s0940-9602(11)80177-9

Cited by 11 publications

(10 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is similar to descriptions in sheep and rat (Gross, 1984;Rudolff et al, 1993;Böckers et al, 1994;Wittkowski et al, 1999). On the other hand, in monkey (macaca fascicularis), the gonadotrope cells are distributed along all the PT (Bock et al, 2001).…”

Section: Discussionsupporting

confidence: 87%

Ultrastructural and immunocytochemical studies of the viscacha (Lagostomus maximus maximus) pituitary pars tuberalis

et al. 2005

View full text Add to dashboard Cite

The hypophyseal pars tuberalis (PT) has been the focus of numerous studies attempting to understand its physiological role in the reproductive regulation and modulation by the neuroendocrine system. Ultrastructural studies of the PT in a number of species have shown that it consists of a well-developed hypophyseal area with important secretory activity, demonstrated by the abundance of secretory granules in the cytoplasm and the marked blood irrigation. This article describes ultrastructural and immunocytochemical aspects of the PT in viscachas captured in their habitat. The cell types identified were PT-specific cells, agranulated cells, and Folliculostellate cells. PT-specific cells are divided into type I and II. Type I cells have cytoplasms with secretory granules of 150-500 nm diameter. The secretory granules of type II PT-specific cells are 65-200 nm in diameter. Both cellular types exhibit numerous nerve endings on the plasmatic membranes. Agranulated cells exhibit nuclei with lax chromatin, mitochondria, phagosomes, scarce Golgi complex, and rough endoplasmic reticulum. Folliculostellate cells exhibit an irregularly shaped and moderately condensed nucleus. All the described cellular types exhibit deposits of cytoplasmic glycogen. The immunocytochemical study revealed the presence of cells immunostained for LH-␤ and FSH-␤ in the PT caudal zone. ACTH was only detected in the zona tuberalis. No staining was observed with antiprolactin, anti-TSH-␤, and anti-GH sera. Folliculostellate cells exhibited staining with anti-S-100. The results demonstrate that the viscacha PT is a hypophyseal zone with specific cellular types, which exhibits evident secretory activity. The presence of nerve endings suggests neural control of the function of PT cells.

show abstract

Section: Discussionsupporting

confidence: 87%

Ultrastructural and immunocytochemical studies of the viscacha (Lagostomus maximus maximus) pituitary pars tuberalis

et al. 2005

View full text Add to dashboard Cite

show abstract

“…In line with our findings these cells are described to be scattered throughout the entire length of the Pt. In other species like sheep or rat distribution of gonadotropic cells is restricted to the caudal part of the Pt [Breitkopf, 1993;Rudolf et al, 1993;Böckers et al, 1994;Wittkowski et al, 1999].…”

Section: Discussionmentioning

confidence: 99%

The Pars tuberalis of the Monkey <i>(Macaca fascicularis)</i> Hypophysis: Cell Types and Hormone Expression

Bock

Böckers

Bockmann

et al. 2001

Cells Tissues Organs

View full text Add to dashboard Cite

The pars tuberalis (Pt) of most mammalian species contains specific cells which are structurally and functionally different from the pars distalis (Pd) cells. Pt-specific cells possess melatonin receptors and reveal morphological changes dependent on the duration of the photoperiod. Furthermore, in hamsters the transmission of photoperiodic stimuli to the endocrine system is influenced by melatonin, an effect which is likely to be mediated by Pt-specific cells. In monkeys, however, only little is known about this cell type. Therefore, we studied the ultrastructural differentiation of Pt-specific cells and describe the expression of different hormones and their mRNA by immunohistochemistry and in situ hybridization. Apparently the Pt consists of (1) cells similar to gonadotropic cells of the Pd, (2) folliculostellate cells and (3) a cell population which is morphologically and functionally clearly distinct from all other cell types found in the Pd. Morphologically they resemble the Pt-specific cells found in other species. Regarding the expression of secretory products there is evidence that they transcribe and translate the β-TSH subunit. Although there is a strong signal for the mRNA of the common α-chain, protein staining is much weaker. POMC mRNA is expressed in the Pt while there is no evidence for PRL mRNA. The present results lead to the conclusion that the Pt of the monkey contains Pt-specific cells which express different hormonal subunits as was already shown for other species. In context with previous findings of melatonin receptors in the monkey Pt further investigations are necessary to establish the possible role of Pt-specific cells in the photoperiod-dependent generation of endocrine rhythms.

show abstract

“…A separate influence over thyroid function, as well as the function of other endocrine axes, may be mediated predominantly via melatonin, an indoleamine secreted by the pineal gland. All cells within the pars tuberalis (PT) of many mammals have been shown to express TSHβ (Rudolf et al, 1993), and mRNA rhythms of this glycoprotein accordingly are modulated by melatonin, peaking just after lights-off (Arai and Kameda, 2004). As circulating melatonin rises in the dark phase, it rapidly inhibits expression of both TSHβ and its heteromeric α-glycoprotein subunit (α-GSU) (Aizawa et al, 2007).…”

Section: The Role Of Circadian Clocks In the Hypothalamic-pituitary Rmentioning

confidence: 99%

Clocks on top: The role of the circadian clock in the hypothalamic and pituitary regulation of endocrine physiology

Tonsfeldt¹,

Chappell²

2012

Molecular and Cellular Endocrinology

View full text Add to dashboard Cite

Recent strides in circadian biology over the last several decades have allowed researchers new insight into how molecular circadian clocks influence the broader physiology of mammals. Elucidation of transcriptional feedback loops at the heart of endogenous circadian clocks has allowed for a deeper analysis of how timed cellular programs exert effects on multiple endocrine axes. While the full understanding of endogenous clocks is currently incomplete, recent work has re-evaluated prior findings with a new understanding of the involvement of these cellular oscillators, and how they may play a role in constructing rhythmic hormone synthesis, secretion, reception, and metabolism. This review addresses current research into how multiple circadian clocks in the hypothalamus and pituitary receive photic information from oscillators within the hypothalamic suprachiasmatic nucleus (SCN), and how resultant hypophysiotropic and pituitary hormone release is then temporally gated to produce an optimal result at the cognate target tissue. Special emphasis is placed not only on neural communication among the SCN and other hypothalamic nuclei, but also how endogenous clocks within the endocrine hypothalamus and pituitary may modulate local hormone synthesis and secretion in response to SCN cues. Through evaluation of a larger body of research into the impact of circadian biology on endocrinology, we can develop a greater appreciation into the importance of timing in endocrine systems, and how understanding of these endogenous rhythms can aid in constructing appropriate therapeutic treatments for a variety of endocrinopathies.

show abstract

Pars tuberalis specific cells within the pars distalis of the adenohypophysis. An ontogenetic study

Cited by 11 publications

References 34 publications

Ultrastructural and immunocytochemical studies of the viscacha (Lagostomus maximus maximus) pituitary pars tuberalis

Ultrastructural and immunocytochemical studies of the viscacha (Lagostomus maximus maximus) pituitary pars tuberalis

The Pars tuberalis of the Monkey <i>(Macaca fascicularis)</i> Hypophysis: Cell Types and Hormone Expression

Clocks on top: The role of the circadian clock in the hypothalamic and pituitary regulation of endocrine physiology

Contact Info

Product

Resources

About