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Biomedical subjects

T Inagami

Publications and source records attributed to T Inagami.

At least 415 records · Page 23Linked to original sources
PubMed1981

Totally inactive renin zymogen and different forms of active renin in hog brain tissues.

The nature of the activable form of renin in the kidney and other tissues has not been clear. Its identification and isolation from kidney have been hampered by rapid activation due to high levels of proteases. Using a pepstatin-Sepharose column, which distinguishes inactive renin from the active enzyme, evidence was obtained for the presence of a totally inactive zymogenic precursor of renin in the pituitary, pineal, and other regions of hog brain. The precursor has an approximate molecular weight of 50,000 and conversion to the active enzyme causes reduction in molecular weight to 43,000. Conversion of this active enzyme to an active but high molecular weight form (60,000) was also observed when the pituitary extract was treated with thiol-blocking reagents. This result was interpreted to indicate the presence of a binding protein. This study has demonstrated that inactive renin zymogen is different from so-called active big renin, which is a complex of active renin and the binding protein.

Animals↗
PubMed1981

Renin in the human kidney. Immunohistochemical localization.

We have localized the enzyme renin (EC 3.4.99.19) in the normal adult human kidney by immunohistology. Serial paraffin sections of kidneys were incubated with renin antisera and then processed by the peroxidase-antiperoxidase method. Renin immunoreactivity was observed in the juxta-glomerular "epithelioid granular cells" (JEG-cells) in the wall of the afferent and rarely of the efferent vessel of the glomerulus. JEG-cells have long cytoplasmic processes penetrating between adjacent cells. This suggests a possible paracrine release of renin. Staining of various segments of the tubular system was shown to be artifactual. The kidney proteins recognized by our anti-human renin antisera had similar characteristics to renin when determined by a combination of gel-electrophoretic and immunologic techniques. Renin immunostaining in the juxtaglomerular apparatus of the human kidney is discrete and reflects the low amount of extractable renin.

Adult↗
PubMed1981

Renin, angiotensins, and angiotensin-converting enzyme in neuroblastoma cells: evidence for intracellular formation of angiotensins.

The mechanism of formation of various peptide hormones in neuronal cells in the brain is not clear. The question of whether brain angiotensin II is formed by an extracellular mechanism as in the peripheral system or by an intracellular mechanism can be answered by using cloned cells in culture. We have screened several neuroblastoma cell lines of rat and mouse origin and found at least three cell lines that contain renin (EC 3.4.99.19), angiotensin-converting enzyme (dipeptidyl carboxypeptidase; peptidyldipeptide hydrolase, EC 3.4.15.1), and angiotensins I and II. This finding was interpreted to indicate that in these cells angiotensin formation takes place by an intracellular mechanism, in contrast to the extracellular mechanism well known to occur in plasma. This study also demonstrates the existence of viable and cloned cell lines that produce renin.

Angiotensin I↗
PubMed1981

Immunohistochemical localization of renin in luteinizing hormone-producing cells of rat pituitary.

The location of renin (EC 3.4.99.19) in rat pituitary was determined by the peroxidase-antiperoxidase immunohistochemical technique. By using antisera prepared with purified rat renal renin, an immunoreactive substance was localized within ovoid cells scattered throughout the anterior pituitary. These cells were shown to be luteinizing hormone-producing cells by staining with anti-luteinizing hormone antisera in adjacent sections. By using the double staining method, the renin-containing cells were differentiated from cells containing corticotropin, thyrotropin, growth hormone (somatotropin), and prolactin (mammotropin). These results suggest a possible local role for renin in the anterior pituitary.

Adrenocorticotropic Hormone↗
PubMed1981

Angiotensin II immunoreactivity coexists with renin in the juxtaglomerular granular cells of the kidney.

The multiple physiologic functions of angiotensin II(AII) are generally supposed to be mediated by the peptide generated in the blood circulation. In addition to this extracellular mechanism of AII formation, we have obtained immunohistochemical evidence for the intracellular synthesis of AII in the kidney. Rats were perfused with fixative, and paraffin sections of the kidneys were processed with antisera against renin (EC 3.4.99.19), AII, and other components of the renin--angiotensin system. Renin immunoreactivity was regularly observed in the epithelioid granular cells in the media of the afferent vessel of the glomerulus. AII immunoreactivity was found to coexist within the same cells. This observation points to an intracellular production of AII in the juxtaglomerular epitheloid granular cells. AII may then be released concomitantly with renin in the interstitial fluid and in the blood. The paracrine secretion of AII could exert a local regulatory influence on the tonus of the glomerular vessels.

Angiotensin II↗
PubMed1981

Localization of renin in trophoblasts in human chorion laeve at term pregnancy.

It is known that renin is present in fetal membranes, with the highest concentration in the chorion laeve (reflected chorion). The purpose of this study was to identify and localize renin in human chorion laeve. Indirect immunofluorescent analysis, using antiserum against pure human kidney renin, revealed a single layer of cells in the chorion with strongly positive fluorescence. The presence of atrophic villi in this layer together with other morphological evidence indicate that the cells which are positive for renin are cytotrophoblasts. Isolated cells were prepared from the chorion by collagenase digestion, followed by filtration and density gradient centrifugation on Percoll. The isolated cells also showed a positive reaction with the immunofluorescent technique. Control experiments with nonimmune serum did not show fluorescent cells. Biochemical analysis using RIA of angiotensin I generated from sheep substrate indicated that most of the renin activity in the isolated cells was present as inactive renin (activated by trypsin). The presence of renin in trophoblastic cells may be of significance in local cardiovascular regulation, events associated with parturition, or pathophysiological manifestations of trophoblastic disease.

Chorion↗
PubMed1980

Renin and prorenin in hog brain: ubiquitous distribution and high concentration in the pituitary and pineal.

With the objective of clarifying the nature of renin-like activity in the brain, we have devised methods to distinguish true renin from acid protease. These methods were used to determine the regional distribution of true renin in hog brain. The pineal was found to be the richest source of renin followed by the adenohypophysis and choroid plexus. The hypothalamus, cerebellum and amygdala contained moderately high concentrations of renin. Renin concentration in the neurohypophysis was negligible. Many regions contained activatable prorenin. The molecular weight and the pH-dependence of the brain renin were identical to these same properties of renal and plasma renins. Based upon its specific affinity to concanavalin A, brain renin was judged to be a glycoprotein. The electrofocusing pattern of renin from different regions of the brain differed from that of plasma and kidney renins, a discrepancy which could be interpreted as evidence for the endogenous synthesis of renin in the brain.

Angiotensin I↗
PubMed1980

Immunohistochemical localization of renin in mouse brain.

Immunohistochemical studies of mouse brain by the peroxidase-antiperoxidase method using monospecific antimouse renin antibodies has revealed the intracellular localization of renin in stellate and small ovoid cells. Renin-containing ovoid cells were observed in the spinal cord, medulla oblongata, pons, granular layers of the cerebellum, deep cerebellar region, and the lamina terminalis; whereas immunostainable stellate cells were found in the cerebral cortex, hippocampus, dentate gyrus and septum. Intracellular localization of renin rather than intravascular localization supports an endogenous origin of this enzyme in the brain. Wide distribution in different types of cells suggests different types of regulatory mechanisms. Double immunostaining with antigalactocerebroside and antirenin antibodies indicates the presence of renin in oligodendrocytes.

Animals↗
PubMed1980

Human renal renin. Complete purification and characterization.

Complete purification of human renin from noncancerous, autopsied kidneys is reported. A 480,000-fold purification was achieved to yield renin with a specific activity of 950 Goldblatt units/mg. This preparation satisfied multiple criteria of purity as tested by polyacrylamide gel electrophoresis, isoelectric focusing, specific activity, analytical ultracentrifugation, and immunodouble diffusion. The molecular weight of the pure enzyme determined by sedimentation equilibrium is 40,000. The apparent molecular weight estimated by gel filtration is 41,000. The enzyme has an isoelectric point of pH 5.7. Human renin shows an affinity for concanavalin A, suggesting the presence of carbohydrates. These properties and the amino acid composition of human renin are different from those of renin obtained from other mammalian species. Human renin antibodies prepared with the pure enzyme preparation showed negligible cross-reactivity with renin from other mammalian species. The activity with homologous human renin substrate has a pH optimum of 6, whereas with substrates from other mammalian species the optima were in higher or lower pH ranges.

Amino Acids↗
PubMed1980

Renin precursor and its activation mechanism in hog kidney.

1. A completely inactive renin was isolated from hog kidney extract by affinity chromatography on pepstatin-aminohexyl-Sepharose and on an Affi-Gel Blue column. 2. This inactive renin had a molecular weight of 43 000 +/- 1500 as determined by gel filtration on Ultrogel AcA 44. Upon activation with trypsin, its molecular weight fell to 41 000 +/- 1400. 3. The inactive renin lacked the ability to bind renin-binding substance whereas trypsin-activated renin was able to bind the renin-binding protein and to form high-molecular-weight renin. 4. Chymotrypsin as well as trypsin could activate the inactive renin although less effectively. 5. The active renins generated from the inactive renin by the action of different proteolytic enzymes differed in their net charge, reflecting the specificities of the proteases used; the isoelectric points of the native, the trypsin-activated and the chymotrypsin-activated forms of renin occurred at pH 5.3, 5.1 and 4.8 respectively.

Animals↗
PubMed1980

Renin in rat and mouse brain: immunohistochemical identification and localization.

1. Localization of renin in rat and mouse brain was determined by immunohistochemical methods with specific anti-renin antibodies. 2. Renin-containing neuronal cells were found in the medulla oblongata, cerebellar nuclei and hypothalamus. Purkinje cells contained renin. 3. Glia-like cells contained renin. Some of them are closely associated with vascular walls and these vascular walls were renin positive. 4. The pineal gland, adenohypophysis and choroid plexus contained renin. 5. The extensive distribution of renin suggests functions other than those which have been associated with the hypothalamus.

Animals↗