Apoptosis in the Anterior Pituitary Gland of the Rat: Studies with Estrogen and Bromocriptine

Drewett, N; Jacobi, Joan; Willgoss, D. A.; Lloyd, Helen

doi:10.1159/000126346

Cited by 84 publications

(46 citation statements)

References 21 publications

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“…Similar structures have been reported by VILA-PORCILE (1973), who suggested that these heterogeneous substances might be the products of the phagocytosis of degenerated glandular cells which have accumulated as residual bodies within the colloid. This interpretation is supported by DREWETT et al (1993), who reported that FS cells phagocytosed apoptotic prolactin cells which appear after the suspension of estrogen treatment, or which appear after the administration of dopamine agonists such as bromocriptine.…”

Section: Electron Microscopic Observationsmentioning

confidence: 66%

“…First, the abundance of lysosomes within them suggests that they may act as scavenger cells (DINGEMANS and FELTKAMP, 1972;VILA-PORCILE,1973;STOKREEF et al, 1986). In this connection, their pronounced phagocytotic activity may have an important role in the removal of apoptotic cells (DREWETT et al, 1993). Secondly, FS cells are known to secrete several growth factors such as fibroblast growth factor (FGF) (FERRER et al, 1987), pituitary-derived vascular endothelial growth factor (PVEGF) (GSPODAROWIC and LAU,1987), follistatin and activin (KATAYAMA et al, 1992;KAISER et al, 1992) and interleukin-6 (IL-6) (VANKELCOM et al, 1989(VANKELCOM et al, , 1993.…”

mentioning

confidence: 99%

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Histochemical Study of Follicles in the Senescent Porcine Pituitary Gland.

Ogawa

Couch

Kubo

et al. 1996

Archives of Histology and Cytology

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Summary. Follicles displaying a positive periodic acidSchiff reaction to a colloid substance in the anterior pituitary gland have been observed in many vertebrates, including humans. It is also known that these follicles greatly increase in number and size with age. We therefore performed histochemical analysis of these colloid follicles in the senescent porcine pituitary gland in order to clarify their nature and biological significance. Results from various histological stains suggest that the colloid contains some polysaccharides or glycoproteins. In addition to the histological stains, lectin histochemistry revealed that the colloid contains sialic acid, N-acetyl galactosamine and galactose. Also, lectin staining indicated that some glycoproteins, most likely Asn-linked sialoglycoproteins, are localized in the colloid. The cells (FS cells) surrounding the colloid were densely stained with an antibody to S-100 protein but were not stained with antibodies to any other anterior pituitary hormones. Frequently mammotrophs (PRL cells), and occasionally gonadotrophs (LH cells) were found closely associated with folliculo-stellate cells ( FS cells) which lay next to the large colloid containing follicles. This suggests that not only are the FS cells important in the production of the colloids, but the adjacent LH and PRL cells in some way also contribute to their formation.Folliculo-stellate cells (FS cells) in the anterior pituitary gland were first described by RINEHART and FARQUHAR in 1953. FS cells were found to completely lack secretory granules and be further characterized by the presence of very long processes which surrounded adjacent glandular cells. The morphology of FS cells therefore suggests that they play an important role in the control of neighboring hormone secreting cells. Several functions have been proposed for FS cells.

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Section: Electron Microscopic Observationsmentioning

confidence: 66%

mentioning

confidence: 99%

Histochemical Study of Follicles in the Senescent Porcine Pituitary Gland.

Ogawa

Couch

Kubo

et al. 1996

Archives of Histology and Cytology

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“…We observed only a small number of TUNEL-positive cells in each pituitary section while there were numerous Bax-immunoreactive cells. This marked difference may be accounted for by the fact that the apoptotic process has very rapid kinetics [7, 19, 29]and dead cells detected by the TUNEL method are rapidly eliminated by phagocytosis from the pituitary tissue by folliculostellate cells found abundantly in the anterior pituitary [9, 30]. Furthermore, it may be possible that high susceptibility to apoptosis as evidenced by Bax expression does not necessarily commit all Bax-immunoreactive cells to apoptotic cell death and only a proportion of the Bax-immunoreactive cells actually undergoes apoptosis in response to apoptotic stimuli.…”

Section: Discussionmentioning

confidence: 99%

“…Studies with animal models have provided some insights into the effects of hormones, particularly ovarian steroids, on cell death of pituitary cells. Drewett et al [9]reported that estrogen withdrawal increases apoptotic cell numbers in the anterior pituitary gland in estrogen-treated rats. This effect is further enhanced by treatment with the dopaminergic agonist bromocriptine.…”

Section: Introductionmentioning

confidence: 99%

Proestrous Surge of Gonadotropin-Releasing Hormone Secretion Inhibits Apoptosis of Anterior Pituitary Cells in Cycling Female Rats

Yin¹,

Ai²

2002

Neuroendocrinology

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Estrogen affects apoptotic cell death in estrogen-responsive tissues. The purpose of the present study was to examine dynamic changes in apoptotic cell death in the anterior pituitary gland during the estrous cycle and to investigate neuroendocrine regulation of these changes in cycling female rats. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) for in situ detection of DNA strand breaks revealed that the number of TUNEL-positive anterior pituitary cells was changing during the estrous cycle, with a maximum in the morning of proestrus and a minimum in the morning of estrus. A similar pattern was observed with Bax immunostaining; however, no difference was observed in Bcl-2 immunostaining. Most of Bax-immunoreactive cells were identified as a subpopulation of gonadotropes. Pentobarbital administered in the afternoon of proestrus attenuated the decrease in TUNEL-positive or Bax-immunoreactive cells in the morning of estrus, although estradiol treatment failed to affect it. This action of pentobarbital was reduced by simultaneous treatment with an ovulation-inducing dose of gonadotropin-releasing hormone (GnRH), but not with progesterone, an ovarian steroid also released after GnRH treatment. These results suggest that anterior pituitary cells, mostly gonadotropes, undergo a cyclic change in apoptotic cell death during the estrous cycle and that the inhibition of apoptosis on estrus is due, at least in part, to the proestrous surge of GnRH secretion.

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“…However to our knowledge the expression of OX6 or other dendritic markers has not been investigated in TtT/GF cells. Ultrastructural studies in rat and guinea fowl have suggested a phagocytic role for F-S cells [111][112][113]. We are not aware of functional studies to support this and have been unable to demonstrate phagocytic activity by native F-S cells or TtT/GF cells, though the very slow turnover of endocrine cells may make this a rather rare event in the adenohypophysis.…”

Section: Communication With the Immune Systemmentioning

confidence: 90%

Folliculo-stellate Cells: Paracrine Communicators in the Anterior Pituitary

Morris¹

2011

TONEUROEJ

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Most research on the anterior pituitary (adenohypophysis) has concentrated on the endocrine cells characterized by their complement of cytoplasmic dense-cored vesicles containing the classic anterior pituitary hormones. However it has become increasingly clear over the last 20 years that cells first identified more than 50 years ago in the basis that they lack such dense-cored vesicles and now known generically as folliculo-stellate or follicular cells have important physiological functions and act as an adenohypophysis wide communication system. This brief review reveals the need for this communication system, what we know of the plethora of products secreted by Folliculo-Stellate cells, the many receptors to which they respond, and in particular, the role of these enigmatic cells in the physiology of the stress/immune axis, the gonadotroph cells and the pituitary vasculature. Finally we review the current evidence that cells in this category can act as stem cells in the adult pituitary.

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Apoptosis in the Anterior Pituitary Gland of the Rat: Studies with Estrogen and Bromocriptine

Cited by 84 publications

References 21 publications

Histochemical Study of Follicles in the Senescent Porcine Pituitary Gland.

Histochemical Study of Follicles in the Senescent Porcine Pituitary Gland.

Proestrous Surge of Gonadotropin-Releasing Hormone Secretion Inhibits Apoptosis of Anterior Pituitary Cells in Cycling Female Rats

Folliculo-stellate Cells: Paracrine Communicators in the Anterior Pituitary

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