Yushi Nakayama

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BACKGROUND/AIMS The blockade of the renin-angiotensin-aldosterone system is the major target of efforts to prevent the progression of chronic kidney disease (CKD). Dual blockade with angiotensin-converting enzyme (ACE) inhibitor and angiotensin II receptor blocker has been reported to show additive renoprotection. However, three types of insertion/deletion(More)
Arginine vasopressin (AVP) and hypertonicity in the renal medulla play a major role in the urine concentration mechanism. Previously, we showed that rat vasopressin V2 receptor (rV2R) promoter activity was increased by vasopressin V2R stimulation and decreased by vasopressin V1a receptor (V1aR) stimulation in a LLC-PK1 cell line stably expressing rat V1aR(More)
Both aldosterone and luminal vasopressin may contribute to the maintenance of acid-base homeostasis, but the functional relationship between these hormones is not well understood. The effects of luminal vasopressin likely result from its interaction with V1a receptors on the luminal membranes of intercalated cells in the collecting duct. Here, we found that(More)
The vasopressin-aquaporin 2 system plays a key role in urine concentration in dehydration. In contrast to the upregulation of aquaporin 2, the downregulation of the vasopressin V2 receptor in dehydration is known. We investigated the mechanisms of this downregulation in dehydration using reverse transcription-competitive polymerase chain reaction(More)
Angiotensin II plays important roles in renal vasoconstriction, sodium reabsorption in proximal tubules, and cell proliferation. Angiotensin II receptors are present not only in proximal but also in distal tubules. We investigated the effects of dehydration on the mRNA expression of type 1A angiotensin II receptor (AT1A) in proximal and distal nephron(More)
Hyperosmolality in the renal medullary interstitium is generated by the renal countercurrent multiplication system, in which the medullary thick ascending limb (MAL) and the outer medullary collecting duct (OMCD) primarily participate. Since arginine vasopressin (AVP) regulates Na-K-ATPase activity directly via protein kinase A and indirectly via(More)
Erythropoietin production has been reported to occur in the peritubular interstitial fibroblasts in the kidney. Since the erythropoietin production in the nephron is controversial, we reevaluated the erythropoietin production in the kidney. We examined mRNA expressions of erythropoietin and HIF PHD2 using high-sensitive in situ hybridization system (ISH)(More)
BACKGROUND Nephrotic syndrome is characterized by severe proteinuria and sodium and water retention. Although endothelin (ET) 1 can cause natriuresis or antinatriuresis, the role played by ET-1 in proteinuria and in sodium retention due to nephrotic syndrome remains unclear. METHODS We investigated the role played by the ET-1 system in sodium and water(More)
A 28-year-old woman with systemic lupus erythematosus was referred to our hospital due to nephrotic-level proteinuria despite approximately 1 year of treatment with 50 to 60 mg/d of prednisolone and 100 to 150 mg/d of cyclosporine with methylprednisolone pulse therapy. Kidney biopsy showed diffuse global lupus nephritis (World Health Organization class 4-G(More)
Angiotensin-converting enzyme inhibitors (ACE-I) have a renoprotective effect in patients with chronic renal failure. Prostaglandins (PGs) have also been shown to ameliorate renal impairment. Although these two have different mechanisms—ACE-I reduces intraglomerular pressure by dilating the efferent arterioles, while it is thought that PGs may increase(More)