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Biomedical subjects

S Morimoto

Publications and source records attributed to S Morimoto.

At least 883 records · Page 49Linked to original sources
PubMed1975

Isolation of peroxisomes from the dog kidney cortex.

The present study was undertaken to separate peroxisomes of the dog kidney cortex by the methods of discontinuous sucrose density gradient and zonal centrifugation. The separation of subcellular particles was evaluated by measuring the activities of reference enzymes, beta-glycerophosphatase for lysosomes, succinate dehydrogenase for mitochondria, glucose-6-phosphatase for microsomes, and catalase and D-amino acid oxidase for peroxisomes. The activities of D-amino acid oxidase and catalase were mainly observed in fractions 1 and 2 (1.6 and 1.7 M sucrose) obtained by discontinuous sucrose density-gradient centrifugation. Small amounts of acid phosphatase and succinate dehydrogenase contaminated these fractions. Considerably higher activity of catalase was determined in the supernatant, while D-amino acid oxidase showed a lower activity. By the method of zonal centrifugation, the highest specific activities of catalase and D-amino acid oxidase were found in fraction 50 (1.73 M sucrose) with no succinate dehydrogenase, acid phosphatase or glucose-6-phosphatase activity. These results suggested that peroxisomes of dog kidney cortex were clearly separated in 1.73 M sucrose from mitochondria, lysosomes and microsomes by zonal centrifugation.

Animals↗
PubMed1975

Suppressed plasma renin activity in adrenal regeneration hypertension.

To clarify the role of the enucleated adrenal in the suppression of plasma renin activity (PRA) in adrenal regeneration hypertension (ARH), PRA response to furosemide administration was compared at the 9th experimental week in three groups of rats, which had been subjected to (a) sham operation (control), (b) unilateral nephrectomy, (c) unilateral nephrectomy plus contralateral adrenal enucleation, and given on tap water or high sodium intakes. Urine volume and sodium, and changes in body weight and hematocrit, determined 90 min after administration of furosemide, did not show any significant differences among any of the experimental groups. The basal PRA was significantly decreased in rats of the other groups as compared to the control rats drinking tap water. A decrease in basal PRA was much more pronounced in the unilaterally nephrectomized rats with or without an enucleated adrenal, drinking saline. After furosemide administration, PRA significantly increased in the control rats drinking saline as well as in the unilaterally nephrectomized rats drinking tap water, with or without an enucleated adrenal, but the PRA values in these three groups were only half those of the control rats drinking tap water. An insignificant increase in PRA was found in unilaterally nephrectomized (plus or minus enucleation) rats drinking saline. These findings suggest that the lack of a PRA response in ARH may be due to the pronounced suppression of the juxtaglomerular cells caused by a high sodium intake and the reduction of the renal mass, independently of the corticosteroid(s) secreted by the enucleated adrenal.

Adrenal Glands↗
PubMed1975

Influence of adrenal enucleation of plasma renin substrate concentration in saline loaded and unilaterally nephroadrenalectomized rats.

The influence of adrenal enucleation on plasma renin substate (PRS) concentration was investigated by comparison with sham operation (control) or adrenalectomy in unilaterally nephroadrenalectomized rats given 1% saline for drinking. Two days after adrenal enculeation or adrenalectomy, a significant increase in plasma renin activity (PRA), with a concomitant decrease in PRS, was observed. Those changes were less pronounced in adrenal enucleated rats than in adrenalectomized ones. Ten days later PRA markedly decreased to the control level in both groups. PRS rose to the control level at 10 days after adrenal enucleation without increasing further, while that in the adrenalectomized rats remained low as before. These results suggest that the fall in PRS occuring immediately after adrenal enucleation may be due both to enhanced PRS consumption resulting from increased PRA and to diminished PRS production caused by corticosteroid deficiency, and that restoration of corticosterone secretion by the enucleated adrenal gland may account for recovery of PRS.

Adrenal Glands↗
PubMed1975

Distribution of renin in subcellular fractions from the rabbit kidney.

Subcellular localization of renin in the rabbit kidney cortex was investigated using two centrifugation techniques. Renin was indirectly assayed on the basis of pressor activity and the reference enzymes such as succinic dehydrogenase, acid phosphatase and D-glucose-6-phosphatase for the other subcellular particulates were biochemically determined. Renin activity was found mainly in the mitochondrial fraction with very little in the microsomal fraction by a differential centrifugation. By a discontinuous sucrose density gradient centrifugation, renin granules were mainly recovered in the fraction corresponding to 1.5 M sucrose, while most of mitochondria, lysosomes and microsome equilibrated in the upper fractions. This renin granular fraction contained approximately 50% of total granular renin activity having a specific activity about six times that seen in the homogenate. After recentrifugation of the renin granular fraction, most of renin activity was recovered in the sediment. Repeated freezing and thawing of this fraction resulted in an increase of renin activity. On the basis of these experimental data it is assumed that renin located in the different subcellular particulates from mitochondria, lysosomes and microsomes in the rabbit kidney cortex.

Angiotensin II↗