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Biomedical subjects

H Sugihara

Publications and source records attributed to H Sugihara.

17 recordsLinked to original sources
PubMed1979

The effect of a low potassium diet on the glomerular zone of the adrenal cortex of rats.

Rats were fed on low potassium diets in order to observe the effect of dietary low potassium on the adrenal cortex. The authors clarified morphological changes of the hypofunctional glomerular zone and compared these changes with those of the hyperfunctional glomerular zone. Three weeks after or 2 months after the start of a low potassium diet, slight narrowing of the glomerular zone of the adrenal cortex was observed followed by miniaturization of cells, presence of binuclear cells and an increase of lipid with enlarged lipid drops. Electron microscope mainly disclosed changes of mitochondrial cristae consisting of markedly reduced, enlarged and irregularly dilated cristae with shortening or elongation. Granules appeared in mitochondria. Lysosomes or dense bodies were enlarged. The Golgi's apparatus was atrophied but endoplasmic reticulum did not show remarkable changes. These changes were directly opposite to those of the hyperfunctional glomerular zone noted after a pottasium load or seen in sodium deficiency. Consequently, these changes were considered to be the changes of the hypofunctional glomerular zone associated with decrease of aldosterone production.

Adrenal Cortex↗
PubMed1979

Effects of glucocorticoids on differentiation of zona glomerulosa of fetal adrenal cortex of rats.

The tissue differentiation of the zona glomerulosa of the fetal adrenal cortex of rats was studied by giving experimental treatments to the fetus in vivo. A low-glucocorticoid-condition was given to the fetus by bilateral adrenalectomy of pregnant rats for removing exogenous glucocorticoids from the fetus, and by brain aspiration of the fetuses for removing the fetal pituitary gland (ACTH) and endogenous glucocorticoids. When the fetus was placed under a low-glucocorticoid-condition for the last couple of days of gestation, poor differentiation of the zona glomerulosa occurred specifically in the fetal adrenal cortex. The degree of the poor differentiation seemed to be proportional to the duration of the low-glucocorticoid-condition. Supplemental administration of glucocorticoids could prevent this poor differentiation of the zona glomerulosa. These results indicate that the tissue differentiation of the zona glomerulosa of the fetal adrenal cortex depends much on glucocorticoids.

Adrenal Cortex↗
PubMed1979

Basal pathomechanism of asthmatic attacks (a review).

Clinical examinations, including provocation, bronchography, electromyography of respiratory muscles, administration of anesthetics and autopsy reject the bronchospasm theory in the production of asthma attacks. Stimulation of sensory nerves, primarily in the upper airway, is the primary basal factor which promotes reflex respiratory activity.

Acetylcholine↗
PubMed1978

The effect caused by the double condition of potassium loading and simultaneous sodium restriction on the glomerular zone of rats. Histochemical and ultrastructural study.

The effect caused by the double condition of potassium loading (K loading) and simultaneous sodium restriction (Na restriction) on the glomerular zone of rats is reported. After 2-week-diet of K loading and simultaneous Na restriction an increase of width of glomerular zone and decreases and micronization of fat granules were seen. Enzymic activity (glucose-6-phosphate dehydrogenase, steroid 3beta-ol-dehydrogenase) was increased. After 3-week-diet of the same condition the width of glomerular zone became 1/4 to 1/5 of the whole cortex. The cells in the glomerular zone demonstrated a trabecular arrangement. Ultrastructurally, hypertrophy of cells became marked and the size of cell was about 1.5 times that of normal cells. Dense body increased in number and became irregular in shape. In the widened cytoplasm, smooth endoplasmic reticulum and Golgi apparatus were well developed with numerous coated vesicles. Changes of mitochondria such as increase in number, transformation into round shape and vesicular cristae were characteristic. The severity of these changes was proportional to the duration of K loading and simultaneous Na restriction. After 8-week-diet the increase of large-sized lipid vacuole and dense body, and intramitochondrial deposition were observed in parallel with the above-mentioned changes. The changes observed in this study appeared earlier and stronger than those in the single-conditioned group of only K loading or Na restriction. The cause of these changes were considered to be a result of accelerated function of the glomerular cells.

3-Hydroxysteroid Dehydrogenases↗
PubMed1977

Effects of exogenous ACTH on the rat fetal adrenal cortex: a histochemical and electron-microscopical observation.

ACTH was administered subcutaneously to rat fetus directly at the late stage of fetal development and acute reaction on the fetal adrenal cortex was observed histochemically and electron microscopically. By administration of ACTH the adrenal cortex became remarkably hyperemic and there were swollen cells in all layers, particularly in the middle and inner layers (corresponding to the zona fasciculata and reticularis in adult rat). Marked reduction of lipid, enlarged mitochondria with increased vesicular cristae and increased smooth-surfaced endoplasmic reticulum (SER) were characteristic. The alterations of mitochondria preceded the change of SER, and thereafter mitochondria showed rapid degeneration. The outer layer (corresponding to the zona glomerulosa in adult rat) also showed similar changes by ACTH to those of the other two layers. These results indicated that the fetal adrenal cortex of rats was exogenous ACTH-reactive and its reaction which was different from that of adult cortical cells, seemed to be specifically related to the development and differentiation of the cells.

Adrenal Cortex↗
PubMed1977

Differentiation of the fetal adrenal cortex of rats--its experimental observation in vivo.

The development and tissue differentiation of the adrenal cortex of rats were studied by giving experimental treatments to the fetus in vivo. A low-ACTH-condition was given to the fetus by administrating Dexamethasone through its mother, or directly into the subcutaneous tissue of the fetus, or by decapitation, brain aspiration or hypophysectomy. When the fetus was given the low-ACTH-condition for the last 5 days or more, the hypoplastic adrenal cortex developed specifically. It had nearly normal zona glomerulosa (ZG), and poorly differentiated zona fasciculo-reticularis (ZF-R) without differentiated ZF-R. The observing day was settled at 21 1/2 days old. The shorter the period of low-ACTH-condition was, the more thickened the differentiated zone (ZF-R) grew. On the contrary, the poorly differentiated layer became thinner in proportion to the period of low-ACTH-condition. The poorly differentiated cortical cell had ACTH-reactivity. It seems that the development and tissue differentiation of the ZF-R depend on fetal own ACTH, and poorly differentiated cortical cells appear below the ZG, and differentiate by ACTH and were gradually pushed inside. The zona glomerulosa develops and differentiates without dependence of ACTH.

3-Hydroxysteroid Dehydrogenases↗