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A Fukamizu

Publications and source records attributed to A Fukamizu.

155 records · Page 9Linked to original sources

Ovarian renin gene expression is regulated by follicle-stimulating hormone.

The regulation of renin and renin messenger RNA (mRNA) in the rat ovary was examined to test the hypothesis that the expression of renin gene and the secretion of renin in the ovary is the estrogen-mediated process that responds to follicle-stimulating hormone (FSH). In the ovary of the immature 25-day female rats, the concentration of renin mRNA was comparatively low, but 36 h after injection of FSH, the renin mRNA content showed a three-fold increase compared to the basal level. This increase was consistent with the stimulation of the total renin concentration in the ovary. On the other hand, the total renin concentration in the rat uterus gradually decreased, suggesting that the enhancement of the contents of renin and renin mRNA by FSH is an ovary-specific phenomenon. In hypophysectomized rats, the total renin concentration in the rat ovary was stimulated by the estrogen as well as FSH. These findings suggest that the production of ovarian renin is regulated by the pituitary hormone, particularly FSH.

Animals↗

Identification of renin and renin messenger RNA sequence in rat ovary and uterus.

An increase in plasma prorenin during pregnancy suggests that prorenin might be synthesized in the ovary and the secretion of renin or prorenin may be stimulated by an ovarian steroid-mediated process. Recently, renin and angiotensinogen have been identified in human ovarian follicular fluid. However, there is considerable controversy over whether renin is synthesized in the ovary or derived from circulation. In the present study, we confirmed the presence of renin and renin mRNA in rat ovary and uterus by Northern blot analysis with rat renin cRNA as a hybridization probe. Our data show that ovarian or uterine renin is synthesized in the same cells. This suggests that the function of renin might be closely linked to the reproductive process.

Animals↗

Human renin gene of renin-secreting tumor.

A large amount of renin mRNA was found to be expressed in the juxtaglomerular cell (JGC) tumor, as determined by Northern analysis. We have isolated the long 5'-flanking region of the human renin gene from the tumor, and characterized the promoter region with respect to nucleotide (nt) sequence and mRNA transcription start point. Of two sets of CAAT and TATA box at 29 bp upstream from the capping site is demonstrated to be a functional promoter by the primer extension. The 1:6-kb sequence, containing the 5'-flanking region, exon 1, and part of the first intron, obtained from the tumor was in complete agreement with that of the clone from fetal liver, which does not produce renin. This indicates that abnormal expression of the human renin gene in the JGC tumor involves no major alteration in the primary structure within 1.2 kb of the 5'-flanking region. Within 1.2 kb of the 5'-flanking region, there are several nt segments exhibiting homology with the glucocorticoid, estrogen, and progesterone receptor-binding sites and enhancers. These structures may be related to the tissue-specific expression of the renin gene.

Amino Acid Sequence↗

Nonfunctioning islet cell carcinoma presenting bleeding gastric varices and splenomegaly.

This is a report of a 63-year-old Japanese woman with a nonfunctioning islet cell carcinoma of the pancreas presenting bleeding gastric varices and splenomegaly. These manifestations are extremely rare in patients with nonfunctioning islet cell tumor. The tumor originated in the tail of the pancreas and grew mainly within the spleen. The gastric varices due to increased blood flow to the tumor and arteriovenous fistulas within the tumor were confirmed by angiography and operation. The tumor was resected and she is in a good health for 14-months after the operation.

Adenoma, Islet Cell↗

Structure of the human renin gene.

The human renin gene was isolated from a Charon 4A human genomic library and characterized. The gene spans about 11.7 kilobases and consists of 10 exons and 9 introns that map at points that could be variable surface loops of the enzyme. The complete coding regions, the 5'- and 3'-flanking regions, and the exon-intron boundaries were sequenced. The active site aspartyl residues Asp-38 and Asp-226 are encoded by the third and eighth exons, respectively. The extra three amino acids (Asp-165, Ser-166, Glu-167) that are not present in mouse renin are encoded by the separate sixth exon, an exon as small as 9 nucleotides. The positions of the introns are in remarkable agreement with those in the human pepsin gene, supporting the view that the genes coding for aspartyl proteinases have arisen as the result of duplication of a common ancestral gene. As in most eukaryotic genes, the putative T-A-T-A and C-A-A-T sequences, which may play a role in the initiation of gene transcription, are found in the vicinity of -29 and -51 nucleotides of the cap site. Further upstream, at nucleotides -456 to -451, is located the hexanucleotide T-G-T-T-C-T, which has recently been suggested as a binding site for the glucocorticoid receptor. In the 3'-flanking region, there is the conserved hexanucleotide sequence A-A-T-A-A-A, thought to be necessary for polyadenylylation. Blot-hybridization analyses of the isolated gene clone and the total cellular DNA after digestion with restriction enzymes revealed that human renin is encoded by a single gene.

Amino Acid Sequence↗

Idiopathic portal hypertension associated with progressive systemic sclerosis.

Herein we describe the clinical course of a case of idiopathic portal hypertension accompanied by splenomegaly, portal hypertension, and pancytopenia in addition to progressive systemic sclerosis. Immunological studies revealed positive antinuclear antibodies, hypergammaglobulinemia with increases in IgG and IgA, a decrease in peripheral T lymphocytes, and a decrease in the rate of lymphocyte blast transformation induced with phytohemagglutinin. The spleen weighed 1070 g, and the portal pressure was 270 nm H2O. Esophageal varices were also noted. These findings suggest the possibility of association of some immunological abnormalities with the etiology of idiopathic portal hypertension.

Adult↗

Changes in the stimulatory capability of mouse small thymocytes to give a proliferation of allogenic spleen cells during differentiation.

Our previous studies on surface antigenic properties of murine small thymocyte subpopulations raised the hypothesis that some of the least dense cells, which possibly were precursor T cells, differentiated into the most dense cells which have the properties of mature T cells. Thus, the stimulatory capacity of the least dense was compared with that of the most dense by one-way mixed leukocyte culture. A marked difference in capacity between both subpopulations was found, i.e., the capacity of the least dense was the strongest of all subclasses, whereas that of the most dense was the weakest. It was concluded from discussions on this difference that the finding supported the hypothesis.

Animals↗

Effects of high-fat diet, angiotensinogen (agt) gene inactivation, and targeted expression to adipose tissue on lipid metabolism and renal gene expression.

To address the role of angiotensinogen (agt) in lipid metabolism and its potential endocrine effects in vivo, we studied the effects of high-fat diet (HFD) on adult, 28-week-old agt knockout (KO) mice compared to wild type (WT) mice. Recent studies (Massiera et al., 2001) have demonstrated that reexpression of agt in adipose tissue of KO mice normalized adiposity, blood pressure, and kidney abnormalities. We therefore used microarray analysis to investigate changes in gene expression profile in kidneys of KO vs. Tg-KO mice, where agt expression is restricted to adipose tissue. Body weight, adiposity and insulin levels were significantly decreased (p < 0.05) in KO mice on a chow diet (CD) compared to WT mice, while circulating leptin levels were similar. On a high-fat diet, KO mice exhibited significantly lower bodyweight (p < 0.05), adiposity (p < 0.05), leptin, and insulin levels (p < 0.05) compared to WT mice. In agreement with previously reported changes in kidney histology, agt KO mice displayed altered expressions of genes involved in blood pressure regulation and renal function, but these levels were corrected by reexpression of agt in adipose tissue. Collectively, these findings further document important endocrine roles of adipocyte agt, in part via regulation of lipid metabolism and kidney homeostasis.

Adipose Tissue↗

Cell type-specific expression of the human renin gene.

We have previously produced transgenic mice carrying the human renin gene, whose expression is regulated in a tissue-specific manner. In the present study, we further characterized expression of the transgene. Northern blot analysis showed that the human renin gene is expressed in the kidney but not in the liver of two lines of transgenic mice with 10 and 50 copies of the transgene, suggesting that the integrated copy number of the human renin gene does not influence the dominant-renal expression pattern. Immunohistochemical study using a monoclonal antibody specific for human renin demonstrated that expression of human renin in the transgenic mouse kidney is confined to the epithelioid juxtaglomerular cells. Transfection experiments indicated that the chloramphenicol acetyltransferase fusion gene containing the 3-kb upstream sequences of the renin gene is activated only in human epithelioid embryonic 293 cells derived from kidney but not in human HepG2 cells from liver. These findings suggest that transfer of the cloned renin gene into mice and in vitro cultured cell lines can give rise to cell type-specific expression.

Animals↗