Comparison de microfractographies types obtenues par microscopie à balayage et par microscopie conventionnelle

Maillard, Arlette; Meny, L.; Champigny, M.

doi:10.1016/0047-7206(70)90030-0

Cited by 1 publication

(4 citation statements)

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“…In the present study, as well as in earlier studies on the ultrastructure of the fetal rat adenohypophysis (Maillard, 1963, Yoshida, 1966, Yoshimura et al, 1970, it has been demonstrated that granulated cells similar to adult hormone-producing cell types are present in the pars distalis several days prenatally. Yoshida, who gave a brief description, found cells with small granules "similar to those of basophils" on the 16th day, and cells with larger granules "acidophilic granulated cells" on the 17th day.…”

Section: ) Correlation Between Ultrastructure and Function Of The Fesupporting

confidence: 83%

“…By centrifugation, Ishikawa also managed to isolate from the adult gland one more fraction of light microscopically chromophobic cells, which electron microscopically were found to contain granules and possess characteristics of ambiguous cells. Cells with the same characteristics were found in fetal rats of the same age by Maillard (1963). During the last five days of intrauterine life, there are cells containing an increased number of granules and with certain characteristics which justify a rough classification into three different types of intermediate cells.…”

Section: ) Cellular Differentiation During Embryonic Developmentmentioning

confidence: 58%

“…Electron microscopically, the presence of non-granulated cells arranged in a follicular pattern in the fetal rat adenohypophysis is well-documented (Maillard, 1963, Yoshida, 1966, Yoshimura et al, 1970. These cells are structurally similar to the marginal cells of the pituitary residual lumen.…”

Section: Introductionmentioning

confidence: 95%

“…In the mouse, as well as in the rabbit, several cell types have already been identified several days before birth (Sano &Sasaki, 1969, andSchechter, 1971). Studying fetal rats on the 18th day of gestation, Maillard (1963) found two types of cells containing granules of mean diameters 350 nm and 160 nm, but referring to the fact that it was not physiologically demonstrated that the secretion of embryonic cells was identical to that of adult cells, she refused to use the nomenclature of adult acidophils and basophils respectively. On the one hand, Yoshida (1966) stated that cells with granules "similar to those of basophils" occurred "almost on the 16th day" and that "acidophilic granulated cells" were seen in 17 day rat embryos.…”

Section: Introductionmentioning

confidence: 99%

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Ultrastructure of the Fetal Rat Adenohypophysis

Svalander¹

1974

Acta Endocrinologica

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and sheep (between 43 and 53 days: Stokes & Boda, 1968). With a similar method, using antibodies conjugated with peroxidase, Nakane (1970) demonstrated the ultrastructural localization of several pituitary hormones in the adult rat. There are no similar electron microscopic studies on fetal rats to be found in the literature.The content of hormones in the fetal pituitary has also been demonstrated in bio-assay or with radio-immune assay methods. By transplantation of fetal pituitaries or injection of pituitary extracts into immature hypophysectomized tadpoles, Enemar (1960b) demonstrated the debut of hormone activities in pituitaries of fetal mice. With this technique, growth-promoting activity was demonstrated at 17.5 days. By in vitro culture of pituitaries and peripheral organs, the presence of hormone in the fetal pituitary may be demonstrated. In this way, Tixier-Vidal (1958) demonstrated the presence of thyrothrophin in the fetal chicken on the 7th day of gestation. Direct demonstration of pituitary hormone content by radio-immune assay has been performed in the fetal rat by Birge et al. (1967), who reported that STH was not present until the 19th day, the concentration then being 0.2 microgram per pituitary. Studies like these may give information on the presence and quantity of trophic hormones in the fetal pituitary, but, as has been emphasized by Moore (1950), conclusions cannot be drawn concerning the ability of the individual pituitary cell to release its hormones in the intact organism.The vascularization of the fetal pituitary is, from a functional point of view, of great interest in two respects, namely, the possible existence of regulatory mechanisms in the fetus between the hypothalamus and the adenohypophysis and also between the adenohypophysis and other organs. The development of the hypophyseal vascular system was thoroughly investigated in the mouse by Enemar (1961), who demon¬ strated in the light microscope that the primary capillary plexus has already developed and has nerve connection in eminentia mediana at 15.5 days, and that a neurovascular communication of adult type is organized by the 17.5 day stage. The appearance of the corresponding neurovascular communication has not been demonstrated in the rat, as far as is known from the literature, but the primary plexus is supposed to be present at the 15.5 to 16.5 day stage (Enemar, 1961). From this stage onwards, the adenohypophysis may be under the influence of hypothalamic centres.

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Section: ) Correlation Between Ultrastructure and Function Of The Fesupporting

confidence: 83%

Section: ) Cellular Differentiation During Embryonic Developmentmentioning

confidence: 58%