Topographical appearance of adenohypophysial cells with special reference to the development of the portal system.

Daikoku, Shigeo; Kawano, Hitoshi; Abe, Kasaburo; Yoshinaga, Koji

doi:10.1679/aohc1950.44.103

Cited by 39 publications

(16 citation statements)

References 18 publications

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“…The FITC-labeled gelatin method revealed that,although the portal vessels had expanded into Atwell's recess by E13.5, they had not entered the pars tuberalis and the pars distalis; by E14.5, the capillaries from the stomatodeal roof had invaded the pars tuberalis. This finding was consistent with previous reports involving the use of Indian ink (Daikoku et al 1981;Szabo and Csanyi 1982). Our isolectin B4 staining method provided additional data indicating the appearance of filopodia, from the primary capillaries, at the tip of portal vessels at E13.5.…”

Section: Discussionsupporting

confidence: 92%

Gene expression of vascular endothelial growth factor-A in the pituitary during formation of the vascular system in the hypothalamic-pituitary axis of the rat

et al. 2006

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Techniques involving fluorescein-5-isothiocyanate-conjugated gelatin injection, immunohistochemistry, and in situ reverse transcription/polymerase chain reaction (RT-PCR) revealed a close relationship between vascular endothelial growth factor (VEGF)-A-expressing cells and microvessels in the hypothalamic-pituitary axis of the rat. In situ RT-PCR clearly indicated the presence of VEGF-A mRNA-expressing cells in the pars tuberalis and in the pars distalis both at embryonic day 15.5 (E15.5) and in later developmental stages. The primary capillaries extended along the developing pars tuberalis, whereas the portal vessels penetrated into the pars distalis at E15.5 and subsequently expanded into the lobe to connect with the secondary capillary plexus, emerging in the pars distalis. At the same time, several VEGF-A-positive cells appeared in the pars distalis. These VEGF-A-positive cells were found to correspond to a portion of adrenocorticotropin (ACTH) cells by dual-staining for in situ RT-PCR and immunohistochemistry, suggesting that some ACTH cells have the potential to produce VEGF-A. Thus, the present study suggests that VEGF-A is involved in the development of the primary capillaries and in the vascularization of the pars distalis, but not in the portal vessels since the formation of portal vessels begins at E13.5, before the appearance of VEGF-A in the rostral region of the pars distalis.

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Section: Discussionsupporting

confidence: 92%

Gene expression of vascular endothelial growth factor-A in the pituitary during formation of the vascular system in the hypothalamic-pituitary axis of the rat

et al. 2006

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“…However, in the rat fetus the hypotha lamic-pituitary system is thought to become functional much later at 15.5 days (0.74) of gestation [3], A more complete understanding of the importance of AVP in the release of ACTH in the young fetus awaits sev eral other lines of evidence. For example, it would be help ful to know whether, in addition to the vascular patency demonstrated in the present study, vessels have morpho logical characteristics such as a fenestrated endothelium typical of neurohemal regions in older fetuses and adults [2].…”

Section: Discussionmentioning

confidence: 99%

Hypothalamic-Hypophyseal Vascular Connections in the Fetal Sheep

1989

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We have studied the development of the hypothalamic-pituitary vascular connections in the fetal sheep using ink-filling techniques. The presence of ink-filled vessels in components of the hypothalamic-pituitary axis is interpreted as indicating patency of the system. Ink-filled vessels were identified in the median eminence, the pituitary stalk and the pituitary gland as early as 45 days of gestation and at all subsequent ages investigated. These results suggest that the pituitary could potentially respond to hypothalamic releasing factors from as early as 45 days of gestation in the fetal sheep.

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“…Stage II (days 9-10): stomodaeal epithelial invagination (pharyngeal diverticulum; Rp) with the superior aspect of the anterior limb in close apposition with the Dd. Stage III (days [11][12]: contacts between the developing Rp and Dd shifted from the anterior-superior region towards the posterior limb of the Rp. The Rp begins to lose its continuity with the oral cavity while precartilaginous condensation of the chondrocranium (basisphenoid and basioccipital cartilages) is evident around the Rp pharyngohypophyseal stalk.…”

Section: Methodsmentioning

confidence: 99%

“…Stage III (days [11][12] Between days 11 and 12, contacts between the developing Rp and the Dd moved gradually from the upper and rostral parts towards the posterior limb. An accumulation of PAS-positive cells was evident in the regions representing initial chondrogenesis of basisphenoid and basioccipital cartilage (Fig.…”

Section: Stage I (Gestational Days 8-9)mentioning

confidence: 99%

Early Organogenesis and Cell Contacts in the Proliferating Hypophysis of the Developing Mouse

Han

Iwai-Liao

Higashi

1998

Okajimas Folia Anatomica Japonica

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Summary: The mouse foetal hypophysis which contains the diencephalic downgrowth (Dd) and Rathke's pouch (Rp) was examined using morphological and immunocyto/histo-chemical methods to study the cell-cell and cell-extracellular matrix (ECM) interactions that occur during early organogenesis. While many studies have described that the differentiation of ACTH cells precedes the proliferation of other endocrine cells in the Rp, light and conventional transmission electron microscopic (TEM) investigations have failed to differentiate between the various endocrine cell types in the proliferating distal lobe at the late mid-foetal stage. Conversely, TEM studies have shown that the occurrence of dense secretory vesicles in glandular cells of the presumptive pars intermedia in dose apposition with the presumptive neural lobe by a basal lamina, is the earliest sign of endocrine activity in the foetal hypophysis. However, a confocal laser scanning microscopy (CLSM) and fine structure study did not observe direct cell-to-cell contacts between the Dd, Rp and their associated mesenchyme at the late mid-foetal stage. Using CLSM and TEM, we detected active cell turnover with programmed cell death in the proliferating Rp, Dd and their associated cephalic mesenchyme. Morphological findings indicated that apoptosis in the cephalic mesenchyme subsequently brings neurohypophyseal pituicytes and adprecursor stem cells into closer proximity, and alternations in the boundary cell surfaces might initiate signal transduction mediated via the intervening ECM at the proliferation stage.

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Topographical appearance of adenohypophysial cells with special reference to the development of the portal system.

Cited by 39 publications

References 18 publications

Gene expression of vascular endothelial growth factor-A in the pituitary during formation of the vascular system in the hypothalamic-pituitary axis of the rat

Gene expression of vascular endothelial growth factor-A in the pituitary during formation of the vascular system in the hypothalamic-pituitary axis of the rat

Hypothalamic-Hypophyseal Vascular Connections in the Fetal Sheep

Early Organogenesis and Cell Contacts in the Proliferating Hypophysis of the Developing Mouse

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