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T Yashiro

Publications and source records attributed to T Yashiro.

At least 91 records · Page 5Linked to original sources
PubMed1982

Fine structural criteria for pituitary thyrotrophs in immature and mature rats.

Fine structural criteria for identifying thyroid-stimulating hormone (TSH) cells in immature and mature rats have been studied by a modified superimposition technique. On days 10 and 20, some small oval immature TSH cells are scattered individually throughout the glandular tissue with a peripheral immunoreactive rim resulting from the sparse distribution of minute secretory granules less than 50 nm in diameter. The immunostained stellate TSH cells are clustered and have secretory granules 50-100 nm in diameter at the cell margins. On day 60, a few small immature TSH cells still remain. Although a few polygonal TSH cells that may not fully mature accumulate secretory granules 100-150 nm in diameter at the cell margins, the majority of TSH cells take the form of large stellate cells filled with secretory granules with the corresponding diameter, and surround an acidophil. These stellate TSH cells are characterized by dense arrangement of parallel arrays of rough endoplasmic reticulum (rER) or rER cisternae. The clustered or isolated elongate TSH cells are also observed to be vesiculated and to have numerous secretory granules 150-250 nm in diameter. In addition, large oval vesiculated TSH cells storing numerous secretory granules 150-250 nm in diameter appear sporadically in the gland, ultrastructurally resembling the gonadotrophs. It is concluded that the rat TSH cell is not a single type with a particular ultrastructure, but modifies its morphology according to its maturation or functional phase.

Aging↗
PubMed1981

A whole range of fine structural criteria for immunohistochemically identified LH cells in rats.

Pituitaries from normal, young and adult male rats were fixed either in sublimate-formalin or in glutaraldehyde-osmium. In adjacent Paraplast sections, almost all the gonadotrophs were immunostained with both LH and FSH antisera. The rat LH beta and FSH antisera used were shown to be highly specific by the absorption test and by double antibody radioimmunoassay. Thin and thick adjacent Epon sections were prepared for EM and immunohistochemical examination. Cells stained with the rat LH beta antiserum were identified by LM, and the observed in detail by EM. On the basis of these observations we suggest that the LH cells are arranged in a sequence of basophils, i.e., Types II/III, III, III/IV and IV: Type II/III basophils are elongate with a cytoplasmic process and less vesiculated. They have morphological features of Type II (classical thyrotrophs) and also of Type III basophils. Type III basophils are oval in shape and moderately vesiculated. Both Types II/III and III basophils can be divided into two classes of cell characterized mainly by the existence of only small secretory granules (150-220 nm in diameter) (Type A) or by the coexistence of small and large (350-500 nm) (Type B). Type III/IV basophils are cells intermediate between types III and IV basophils, and moderately vesiculated with an abundance of secretory granules (150-300 nm in diameter). Type IV basophils are large, spherical or oval cells whose RER cisternae are conspicuously dilated; they contain less numerous secretory granules (150-300 nm in diameter). It is concluded that LH cells are not a single cell type, but include a wide range of subtypes.

Animals↗
PubMed1981

Immunohistochemical study of the postnatal development of pituitary thyrotrophs in the rat, with special reference to cluster formation.

The postnatal development of rat pituitary thyrotrophs was investigated immunohistochemically on days 1, 3, 5, 10, 15 and 25. Fetal thyrotrophs are strongly immunoreactive. In the postnatal period, however, weakly immunoreactive thyrotrophs increase in number to constitute clusters on days 3--5. The numbers and dimensions of the clusters reach a maximum on day 10. Thereafter the clusters break down to give rise to single, scattered neogenic thyrotrophs. Thyrotrophs in clusters on day 10 were investigated by electron microscopy in adjacent sections. They can be characterized as an immature type of basophil, according to the classification of Yoshimura et al. (1977): 1) Type I basophils, which are irregularly shaped with elongate processes, and characterized by rows of secretory granules about 100 nm in diameter. 2) Type I/II basophils, i.e., forms intermediate between Types I and II, containing less numerous secretory granules about 100--150 nm in diameter. Type II basophils which correspond to the classical thyrotrophs are not fully developed on day 10. Thus, most thyrotrophs develop from the clusters in the neonatal period. Such neogenic thyrotrophs retain the immature characteristics of Type I and I/II cells and may develop into Type II cells during subsequent maturation.

Animals↗