Ultrastructural localization of immunoreactive corticotropin, ?-lipotropin, ?- and ?-endorphin in Cells of the human fetal anterior pituitary

1979 ◽  
Vol 204 (1) ◽  
Author(s):  
J.Y. Li ◽  
M.P. Dubois ◽  
P.M. Dubois
Keyword(s):  
Anterior Pituitary ◽  
Ultrastructural Localization ◽  
In Cells

Ultrastructural localization of sialylated glycoconjugates in cells of the salamander olfactory mucosa using lectin cytochemistry

1992 ◽  
Vol 267 (1) ◽  
pp. 113-124 ◽  
Author(s):  
James D. Foster ◽  
Marilyn L. Getchell ◽  
Thomas V. Getchell
Keyword(s):  
Ultrastructural Localization ◽  
Olfactory Mucosa ◽  
Lectin Cytochemistry ◽  
In Cells

Ultrastructural localization of exogenous silver in the anterior pituitary gland of the rat

1984 ◽  
Vol 41 (1) ◽  
pp. 58-66 ◽  
Author(s):  
Ole Thorlacius-Ussing ◽  
Jørgen Rungby
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Ultrastructural Localization ◽  
Anterior Pituitary Gland

scholarly journals Ultrastructural localization of prolactin in the rat anterior pituitary glands by preembedding peroxidase-labeled antibody method: observations in normal, castrated, or estrogen-stimulated specimen.

1982 ◽  
Vol 30 (9) ◽  
pp. 919-925 ◽  
Author(s):  
R Y Osamura ◽  
N Komatsu ◽  
S Izumi ◽  
S Yoshimura ◽  
K Watanabe
Keyword(s):  
Anterior Pituitary ◽  
Secretory Granules ◽  
Ultrastructural Localization ◽  
Pronounced Increase ◽  
Alternative Pathways ◽  
Antibody Method ◽  
Pituitary Glands ◽  
Normal Rat ◽  
Estrogen Stimulation

Ultrastructural localization of prolactin (PRL) was studied immunocytochemically (preembedding peroxidase-labeled antibody method) in a variety of pituitaries, including those from 1) normal, 2) castrated, and 3) castrated and estrogen-stimulated rats. In the normal rat, PRL was observed in cisternae of the rough endoplasmic reticulum (RER), perinuclear spaces, Golgi saccules, and secretory granules. In the castrated rats, PRL cells were rather atrophic and were filled with many small PRL-positive secretory granules. RER and Golgi saccules were rather inconspicuous and were almost devoid of PRL localization. The serum PRL level was markedly lowered. With estrogen stimulation after castration, the serum PRL level was markedly elevated and PRL cells showed a pronounced increase of PRL filled cisternae in the RER. From these observations, the role of secretory granules, Golgi apparatus, and RER in hormonal secretion was defined, and it was postulated that some peptide hormones would be secreted along two alternative pathways, i.e., either 1) a long (regulated) pathway or 2) a short (accelerated) pathway, in accordance with their secretory activities, which could be altered by various stimulations such as the use of estrogen.

scholarly journals Tanycyte Pyroglutamyl Peptidase II Contributes to Regulation of the Hypothalamic-Pituitary-Thyroid Axis through Glial-Axonal Associations in the Median Eminence

Endocrinology ◽  
2009 ◽  
Vol 150 (5) ◽  
pp. 2283-2291 ◽  
Author(s):  
Edith Sánchez ◽  
Miguel Angel Vargas ◽  
Praful S. Singru ◽  
Isel Pascual ◽  
Fidelia Romero ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Median Eminence ◽  
Anterior Pituitary ◽  
Cellular Localization ◽  
Third Ventricle ◽  
Male Rats ◽  
Mediobasal Hypothalamus ◽  
External Zone ◽  
The Third ◽  
In Cells

Pyroglutamyl peptidase II (PPII), a highly specific membrane-bound metallopeptidase that inactivates TRH in the extracellular space, is tightly regulated by thyroid hormone in cells of the anterior pituitary. Whether PPII has any role in the region where axons containing hypophysiotropic TRH terminate, the median eminence, is unknown. For this purpose, we analyzed the cellular localization and regulation of PPII mRNA in the mediobasal hypothalamus in adult, male rats. PPII mRNA was localized in cells lining the floor and infralateral walls of the third ventricle and coexpressed with vimentin, establishing these cells as tanycytes. PPII mRNA extended in a linear fashion from the tanycyte cell bodies in the base of the third ventricle to its cytoplasmic and end-feet processes in the external zone of the median eminence in close apposition to pro-TRH-containing axon terminals. Compared with vehicle-treated, euthyroid controls, animals made thyrotoxic by the ip administration of 10 μg l-T4 daily for 1–3 d, showed dramatically increased accumulation of silver grains in the mediobasal hypothalamus and an approximately 80% increase in enzymatic activity. PPII inhibition in mediobasal hypothalamic explants increased TRH secretion, whereas ip injection of a specific PPII inhibitor increased cold stress- and TRH-induced TSH levels in plasma. We propose that an increase in circulating thyroid hormone up-regulates PPII activity in tanycytes and enhances degradation of extracellular TRH in the median eminence through glial-axonal associations, contributing to the feedback regulation of thyroid hormone on anterior pituitary TSH secretion.

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