Localization and functional characterization of rat kidney-specific chloride channel, ClC-K1.

To investigate the physiological role of a kidney-specific chloride channel (ClC-K1), we sought to determine its exact localization by immunohistochemistry and its functional regulation using Xenopus oocyte expression system. The antiserum specifically recognized a 70-kD protein in SDS-PAGE of membrane protein from rat inner medulla and an in vitro translated ClC-K1 protein. Immunohistochemistry revealed that ClC-K1 was exclusively localized to the thin limb of Henle's loop in rat inner medulla. In comparison with the immunostaining with anti-aquaporin-CHIP antibody that only stains the descending thin limb of Henle's loop (tDL), ClC-K1 was found to be localized only in the ascending limb (tAL) which has the highest chloride permeability among nephron segments. Immunoelectron microscopy confirmed that the staining of ClC-K1 in tAL was observed in the region of both apical and basolateral plasma membranes. Expressed chloride current in Xenopus oocytes by ClC-K1 cRNA was regulated by extracellular pH and extracellular calcium. Furosemide inhibited the expressed current (Ki = 100 microM), whereas N-ethyl-maleimide stimulated the current. These functional characteristics were consistent with the in vitro perfusion studies of chloride transport in tAL. The localization and the functional characteristics described here indicate that ClC-K1 is responsible for the transepithelial chloride transport in tAL.

Similar Anemic Control Between Chronic Kidney Diseases in Patients With and Without Transplantation on Entry to Dialysis.

BACKGROUND: Transplant recipients are supposedly in a more anemic, catabolic, and even inflammatory state at re-entering hemodialysis due to chronic rejection. The goal of this study was to clarify how transplant recipients can re-enter dialysis safely by focusing on control of anemia. METHODS: From 2012 to 2014, a total of 29 transplant recipients re-entered hemodialysis because of chronic rejection (ie, the chronic kidney disease with transplant [CKDT] group). At the same time, in 2014, a total of 30 patients with chronic kidney disease without transplantation entered dialysis as the control group (ie, the CKD group). CKDT recipients (mean ± standard deviation age, 41.9 ± 11.8 years; 18 male subjects, 10 female subjects; frequency of diabetes, 10%; duration of graft survival, 12.5 ± 4.3 years) were younger and fewer had diabetes compared with the CKD group (age, 53.2 ± 10.5 years; 21 male subjects, 9 female subjects; frequency of diabetes, 36%). Patient characteristics at entering dialysis in both groups were analyzed according to retrospective chart review. RESULTS: At entering dialysis, there were no significant differences between the CKD and CKDT groups in terms of the following: dose of darbepoetin; concentrations of hemoglobin, albumin, and C-reactive protein; cardiothoracic ratio; blood urea nitrogen and creatinine levels; estimated glomerular filtration rate; initial ultrafiltration; and duration of hospitalization for initiation of dialysis. The only difference between groups was mean weight at entry to dialysis (CKDT group, 58.5 ± 15.1 kg; CKD group, 67.1 ± 14.8 kg; P = .03). The darbepoetin dose per kilogram of weight did not differ between groups (CKDT, 2.28 ± 2.03 µg/kg; CKD, 2.12 ± 1.6 µg/kg; P = .95) in the final month before entry to dialysis. CONCLUSIONS: Safe re-initiation of dialysis is important for recipient survival. Although anemia is supposedly higher in transplant recipients due to immunosuppression, this single-center analysis found no difference in anemia in CKD with or without transplantation, caused by good use of erythropoietin-stimulating agents in both groups.

Pharmacokinetic Profile of Twice- and Once-daily Tacrolimus in Pediatric Kidney Transplant Recipients.

BACKGROUND: The aim of this study was to assess the differences in pharmacokinetic (PK) profiles after the 1:1 ratio-based conversion from a twice-daily to a once-daily tacrolimus formulation (TD-TAC and OD-TAC, respectively) in pediatric recipients of kidney transplants. METHODS: TD-TAC was initially administered to 29 pediatric patients who underwent kidney transplantations between April 2010 and September 2015 and were then subsequently switched to OD-TAC. The switch dose ratio was 1:1, and the 24-hour complete PK parameter assessment was performed before and after the regimen was changed from TD-TAC to OD-TAC. RESULTS: The mean total daily dose at baseline was 5.5 ± 2.9 mg (0.18 ± 0.10 mg/kg body weight). Consecutive PK studies revealed no significant difference in the mean time to achieve maximum concentrations and the area under the concentration-time curve from 0 to 24 hours (AUC0-24) of both drug formulations. However, the mean trough concentration (Cmin) and the maximum concentration of OD-TAC were 22% and 6% lower and higher, respectively, than those of TD-TAC. Therefore, a better correlation was observed between the AUC0-24 and Cmin of OD-TAC than between those of TD-TAC. CONCLUSIONS: After the change from TD-TAC to OD-TAC, the AUC0-24 values were equivalent despite a 22% reduction in Cmin. Cmin may therefore be an excellent predictor in the therapeutic drug monitoring of OD-TAC because of its superior correlation with AUC0-24.

Effects of long-term treatment with mizoribine in patients with proliferative lupus nephritis.

AIM: Mizoribine (MZR) is a purine antimetabolic immunosuppressant agent that has few little severe adverse events. We studied whether maintenance therapy with MZR and prednisolone (PSL) in severe proliferative lupus nephritis patients could improve immunity, reduce proteinuria, prevent renal relapse, and reduce steroid dose. METHOD: Long-term maintenance therapy with MZR and PSL was evaluated in ten patients with biopsy-proven proliferative lupus nephritis. Patients with severe lupus nephritis, who had proteinuria of 0.5 g or more even after treatments with plasma exchange and/or pulse methyl prednisolone, were recruited. MZR at an average dose of 140 +/- 10 (100 - 200) mg was administered two to three times/day in combination with PSL. The average period for the MZR maintenance therapy was 89.7 +/- 5.5 (70 - 126) months. Urine protein excretion, serum hemolytic complement activity (CH50), C3, serum creatinine, general and biochemical blood examinations, anti-ds-DNA antibody were collected at each monthly medical examination. RESULTS: All patients were females, mean age 43.0 +/- 3.3 years. A significant decrease in proteinuria was noted two years after the combination therapy (p = 0.0016). Five patients experienced lupus nephritis relapse. Patients who did not experience relapses had their MZR combination therapy initiated earlier (p = 0.037) when compared with the patients who experienced relapses. Serum creatinine levels remained unchanged in all patients throughout treatment and follow-up, even during renal relapses. Levels of C3 and CH50 normalized as proteinuria decreased. None of the patients developed serious side effects during MZR treatment. A significant steroid-sparing effect was observed three years after initiating MZR (p = 0.0025). CONCLUSION: From our long-term observation, maintenance therapy with low-dose PSL combined with MZR can eliminate proteinuria and have steroid-sparing effect. Early initiation of the therapy can protect against renal relapses among severe proliferative lupus nephritis patients without serious side effects.

Glomerular expression of cell-cycle-regulatory proteins in human crescentic glomerulonephritis.

To elucidate the mechanism underlying crescentic formation, we assessed the phenotypic characterization and cell-cycle protein expression in human crescentic glomerulonephritis (CRGN). Kidney tissue specimens taken from CRGN patients (10 patients with pauci-immune type rapidly progressive glomerulonephritis (RPGN), 2 patients with Henoch-Schönlein purpura nephritis, and 1 patient with IgA nephropathy) were examined immunohistochemically. Most of the cellular components of the crescents expressed cytokeratin, whereas few cells expressed PHM-5. CD68-positive cells were minor components of cellular crescents, indicating that the major principal cellular component of the crescents is made up of cells with the parietal glomerular epithelial cell (PEC) phenotype. Additionally, serial section analysis revealed that Ki-67-positive cells in the crescents were frequently cyclin-A positive and Bcl-2 positive, but seldom cyclin-B(1) positive. Moreover, the expression of cyclin-dependent kinase inhibitor p27(Kip1) was low in the cellular crescents, despite being exclusively positive in podocytes within the same section. We concluded that the major component of the cellular crescents is made up of PECs and that apparent expression of cyclins and Bcl-2 and restrained expression of p27(Kip1) may be synergistically associated with the development of cellular crescents in human CRGN.

Nitric oxide synthase I immunoreactivity in the macula densa of the kidney is angiotensin II dependent.

The present study was undertaken to clarify the mechanism of the regulation of nitric oxide synthase (NOS)-I in the macula densa of the kidney. We determined the changes in NOS-I immunoreactivity of the macula densa relevant to the changes in systemic blood pressure (BP) and the renin-angiotensin system. Rats received four different types of treatment, and kidney sections were immunohistochemically stained for renin, NOS-I, and NOS-III. Plasma renin activity (PRA) and angiotensin II (Ang II) concentration were determined by radioimmunoassay. In the low-salt group, PRA, plasma Ang II, and the number of renin and NOS-I positively stained areas in the juxtaglomerular apparatus (JGA) were all increased, while BP and NOS-III in the glomerular capillaries did not change. In the desoxycorticosterone acetate (DOCA)-salt group, in contrast to the elevation of BP, PRA, plasma Ang II, and all immunohistochemical parameters were decreased. In the Ang II infusion group, BP, plasma Ang II, and the number of NOS-I positive glomeruli were increased, while PRA and renin staining were decreased. Administration of Ang II type 1 receptor (AT-1) antagonist TCV-116 significantly increased PRA, plasma Ang II, and the number of renin-positive glomeruli. However, BP, and NOS-I and NOS-III staining did not show any difference. These results clearly suggest that NOS-I in the macula densa changes in parallel with plasma Ang II, but not renin or systemic BP.

The K(ATP) channel opener nicorandil: effect on renal hemodynamics in spontaneously hypertensive and Wistar Kyoto rats.

Adenosine triphosphate-sensitive K channels (K(ATP)) may subserve vasodilation in the renal microvasculature. Using micropuncture techniques, we examined whether the renal vasomotor action of K(ATP) differs in hypertensive and normotensive animals. Nicorandil (NC), a K(ATP) opener, was given i.v. (1 mg/hr/kg) to spontaneously hypertensive rats (SHR) or Wistar Kyoto rats (WKY). Mean arterial blood pressure decreased in both groups. Renal blood flow was almost unchanged in SHR but increased significantly in WKY. This effect was completely abolished by pretreatment with glibenclamide (GC; 3 mg/kg i.v.). To investigate the effect of NC on the regulatory mechanism of renal microcirculation, we measured proximal tubular stop-flow pressure (SFP) and assessed tubuloglomerular feedback (TGF) by monitoring SFP during loop perfusion with artificial tubular fluid. NC significantly increased SFP in WKY, an effect abolished by pretreatment with GC. In SHR, however, treatment with NC elicited no significant change in SFP. TGF response was not affected by NC treatment in either group. The data suggest that K(ATP) may modulate preglomerular vascular resistance, especially in the larger vascular segments not subject to TGF regulation, and may be attenuated in SHR. This might, at least in part, be attributable to the increased vascular resistance in SHR.

Dynamic computer tomography is useful in the differential diagnosis of juxtaglomerular cell tumor and renal cell carcinoma.

We compared dynamic computer tomographic CT images of 3 cases of juxtaglomerular (JG) cell tumor with those of 8 cases of renal cell carcinoma (RCC). The JG cell tumor was visualized as a low- to high-density area in case 1, a low-density area in case 2, and a low- to iso-density area in case 3 before contrast enhancement. None of the JG cell tumors were stained during the early phase (1 min), but all were stained moderately during the late phase (5 min) after contrast enhancement. Although all cases of RCC were visualized as a low- to iso-density area before contrast enhancement, they were intensely stained during the early phase with significant washout during the late phase. The present results suggest that the dynamic CT scan is useful in the differential diagnosis of the JG cell tumor and RCC.

Endothelin-1 mediates erythropoietin-stimulated glomerular endothelial cell-dependent proliferation of mesangial cells.

These experiments were performed in an attempt to determine whether chronic stimulation of glomerular endothelial cells with recombinant human erythropoietin would alter mesangial cell proliferation. Glomerular endothelial cells in culture incubated with various concentrations of erythropoietin for up to 4 days exhibited dose-dependent endothelin-1 production. Moreover, the conditioned medium from erythropoietin-stimulated glomerular endothelial cells enhanced [3H]thymidine incorporation into mesangial cells. This enhancement was significantly attenuated in the presence of a endothelin A receptor antagonist, BQ-123. These results suggest that endothelin-1 mediates erythropoietin-stimulated glomerular endothelial cell-dependent mesangial cell proliferation, resulting in the progression of glomerulonephritis.

The attenuated effect of ATP-sensitive K+ channel opener pinacidil on renal haemodynamics in spontaneously hypertensive rats.

In hypertension, impairment of hyperpolarization by K+ efflux through ATP-sensitive K+ (K(ATP)) channels may contribute to the elevated renal vascular resistance. To elucidate such a role for K(ATP) channels in the renal vasculature, we used micropuncture techniques to examine the effect of K(ATP) channel opener, pinacidil (0.15 mg/h per kg body wt i.v.), on renal and glomerular haemodynamics in spontaneously hypertensive rats (SHR) and in normotensive controls (Wistar Kyoto, WKY). Since pinacidil reduced blood pressure significantly in both groups, the abdominal aorta was clamped before pinacidil administration to yield a renal perfusion pressure equivalent to that during pinacidil infusion. Pinacidil significantly decreased renal vascular resistance in both groups, but the relative change from baseline value was greater in WKY than in SHR. These effects of pinacidil were abolished by pretreatment with glibenclamide (3 mg/kg body wt i.v.). Proximal tubular stop-flow pressure (Psf), an index of glomerular capillary pressure, was significantly elevated by pinacidil infusion in WKY, a response abolished by pretreatment with glibenclamide, but not in SHR. The tubuloglomerular feedback response of Psf was not affected by pinacidil in either group. These data suggest that the activity of K(ATP) channels in SHR may be attenuated in the renal microvasculature. This may contribute to the elevated vascular tone in the renal preglomerular vasculature in SHR.

Recombinant human erythropoietin stimulates vascular endothelial growth factor release by glomerular endothelial cells.

We designed the present study to address the question of whether recombinant human erythropoietin stimulates DNA synthesis and vascular endothelial growth factor (VEGF) secretion in vitro using cultured bovine glomerular endothelial cells (GENs). Recombinant human erythropoietin dose-dependently stimulated the proliferation of GENs in culture, and this proliferative effect was inhibited by 1 microg/ml anti-VEGF antiserum. The increase in VEGF concentrations in the supernatants containing 10 U/ml rHuEpo was abolished by incubation with 10 microg/ml of anti-human rHuEPO antiserum, 0.2 microg/ml actinomycin D or 10 microg/ml cycloheximide. Taken together, rHuEpo stimulates GEN proliferation in vitro and VEGF release from these cells is associated with stimulation of RNA-dependent DNA and protein synthesis.

Nipradilol inhibits DNA synthesis by regulating nitric oxide synthesis in cultured rat mesangial cells.

To elucidate whether nipradilol modulates mesangial cell function, we assessed the effects of nipradilol on DNA synthesis in the presence and absence of N-nitro-L-arginine methyl ester (L-NAME) in cultured rat mesangial cells stimulated with 1% fetal bovine serum. Nipradilol inhibited [3H]thymidine incorporation into mesangial cells in a dose- and time-dependent manner. In addition, the anti-mitogenic effect of 100 microM nipradilol was significantly inhibited in the presence of 10 microM L-NAME. Moreover, nipradilol increased intracellular cyclic guanosine monophosphate (cGMP). These results suggest that nipradilol exerts its efficacy in the treatment of several types of glomerulonephritis with mesangial cell proliferation by increasing in intracellular cGMP.

Measurement of urinary annexin V by ELISA and its significance as a new urinary-marker of kidney disease.

To confirm the significance of excretion of annexin V into the urine and the change of urinary annexin V concentration in kidney disease, a sandwich enzyme-linked immunosorbent assay (ELISA) was developed using two monoclonal antibodies. Urinary annexin V concentration was measured in healthy individuals and patients with kidney and other diseases. Urinary annexin V did not change over a range of pH between 5.0 and 8.0, and was stable during the course of the study for 24 h at room temperature and for 8 days at 4 degrees C. The mean urinary annexin V concentration in 105 normal healthy individuals was 1.5+/-1.5 ng/ml, while that in patients with nephrotic syndrome and systemic lupus erythematosis (SLE) nephritis was 9.3+/-9.1 and 6.6+/-6.7 ng/ml, respectively, and that in IgA nephropathy and chronic renal failure was 2.6+/-2.1 and 1.3+/-0.7 ng/ml, respectively. Annexin level correlated with urinary protein concentration (r=0. 717), but not the serum creatinine concentration, blood urea nitrogen (BUN) and 24-h creatinine clearance. Mean urinary annexin V concentration in patients with ischemic heart disease, hypertension, and diabetes mellitus was 1.4+/-1.0, 1.4+/-1.1, and 1.7+/-1.3 ng/ml, respectively. In one case of relapsing nephrotic syndrome, the urinary annexin V concentration was markedly increased in the early phase after admission and then decreased. This patient later required hemodialysis. These results suggest that a high urinary annexin V concentration may be an indicator of acute renal injury related to the urinary protein level.

Effect of subarachnoid hemorrhage on serotonin uptake and release in the rabbit basilar artery.

This study analyzes the changes induced by subarachnoid hemorrhage (SAH) on the serotonin (5-hydroxytryptamine, 5-HT) uptake and release evoked in rabbit basilar arteries by tyramine. Rabbits were injected with 5 ml of autologous arterial blood into the cisterna magna to produce SAH. Tritium accumulation in basilar arteries was measured after 30 minutes of incubation with 10(-7) M [3H]5-HT and a subsequent 120-minute superfusion (1 ml/min) period. The uptake of 5-HT by arteries 1, 2, 3, and 7 days after SAH was found to be 109%, 69%, 57% (P less than 0.05), and 67% (P less than 0.05) (n = 4, 4, 9, and 6; P less than 0.05) of control (n = 13; 16.8 +/- 1.2 X 10(2) dpm/mg tissue), respectively. The neuronal (cocaine-sensitive) uptake of 5-HT in the arteries 3 days after SAH decreased to approximately 38% of control, whereas the extraneuronal (cocaine-insensitive) uptake of both groups had almost the same absolute value (n = 6 and 6; 4.4 +/- 0.4 and 4.8 +/- 0.4 X 10(2) dpm/mg). Autoradiographic study disclosed that dense clusters of silver grains in the adventitia were not observed after treatment with cocaine (3 X 10(-5) M), although a diffuse distribution of grains was present throughout the vascular wall. The labeled arteries were stimulated by superfusion of tyramine, which is known to replace amines in the sympathetic nerve ending. Tyramine (10(-6) and 10(-4) M)-induced 3H efflux was significantly potentiated by SAH (n = 6) and was suppressed by treatment with cocaine.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral uric acid, xanthine, and hypoxanthine after ischemia: the effect of allopurinol.

The existence of uric acid in mammalian brain was recently reported, but it has not yet become a consensus. The mammalian brain has been thought to lack xanthine oxidase, which catalyzes hypoxanthine to xanthine and xanthine to uric acid as the last steps of ATP degradation in other tissue. Using high-performance liquid chromatography, we performed assays for hypoxanthine, xanthine, and uric acid in rat brain after cerebral ischemia. It was confirmed that all three substances showed significant augmentation in the removed brains and that the chronological order of those increases corresponded to the order in the metabolic pathway. Allopurinol, a specific inhibitor of xanthine oxidase, significantly suppressed the increases in uric acid and xanthine, and a compensatory accumulation of hypoxanthine was observed. From these results, it was concluded that uric acid does exist in the brain, increases after ischemia, and is possibly the end product of purine degradation in the brain. Furthermore, it is suggested that xanthine oxidase exists in the brain and catalyzes the reaction from hypoxanthine to xanthine and then to uric acid. These reactions catalyzed by xanthine oxidase are considered to be a source of free radicals and may play important roles in the pathogenesis of cerebral ischemic injury.

Theoretical comparison of surgery and radiosurgery in cerebral arteriovenous malformations.

OBJECT: Management of patients with cerebral arteriovenous malformations (AVMs) is controversial. Excellent surgical results are obtained in patients with low Spetzler-Martin grades, whereas radiosurgery offers a good alternative with its high obliteration rate. In the absence of randomized studies, physicians must choose a treatment plan based on the currently available data. To support this decision-making process, a mathematical model designed to describe patient survival rates after each treatment option was developed. METHODS: The theoretical survival curve in patients undergoing conventional surgery, radiosurgery, or observation was calculated. Theoretical life expectancies in patients with AVMs who presented at various initial ages were calculated for each treatment strategy. A systematic method was also developed to compare the estimated risks of various treatment combinations. CONCLUSIONS: Conventional surgery and radiosurgery definitely produced better survival rates than observation. In the comparison of surgery with radiosurgery, radiosurgery was equivalent to surgery with a combined morbidity and mortality rate of approximately 7% for a 20-year-old patient with an unruptured cerebral AVM. Data for other patient ages and treatment combinations are tabulated for use in determining the best treatment strategy. The authors believe that their analysis will provide logical support for the decision-making process involved in the treatment of patients with cerebral AVMs.

Glomerular endothelial cells promote mesangial cell growth via a PDGF-Like substance.

We conducted these experiments to determine whether glomerular endothelial cells (GEN) may play a role in the regulation of glomerular mesangial cells (GMC) growth. When GMC were separately co-cultured with GEN for 24 h, [3H]thymidine incorporation into GMC increased by 22%. In addition, when GMC were co-cultured with GEN for 4 days, the GMC count increased statistically. Conditioned medium (CM) was obtained from confluent GEN monolayers and tested for its effect on GMC growth. When CM was mixed with RPMI 1640 medium containing fetal calf serum (final concentration: 10%), GMC growth was potentiated in a dose-dependent manner. This stimulatory effect of CM from GEN cultures was inhibited by the addition of anti-human platelet-derived growth factor (PDGF) antibody. However, antibodies against interleukin 1-beta, tumor necrosis factor-alpha and endothelin-1 did not affect the stimulatory effect of CM. Moreover, the modulator contained in CM was stable at 100 degrees C, and pH 2.5 at 22 degrees C for 30 min. When treated with 2 mM mercaptoethanol, this activity was almost completely lost. These findings suggest that GEN promote GMC growth in co-culture systems, without direct contact, by means of a PDGF-like substance.

Anti-mitogenic effects of sarpogrelate in cultured rat mesangial cells.

We investigated the effects of the new 5-HT2A receptor antagonist, sarpogrelate, on DNA synthesis in renal mesangial cells stimulated with 5-HT in the presence and absence of platelet-derived growth factor (PDGF)-BB. Both 5-HT and PDGF-BB demonstrated a mitogenic effect on these cells. When mesangial cells were incubated in the absence of PDGF-BB, sarpogrelate inhibited DNA synthesis in these cells in a dose-dependent manner. In the presence of PDGF-BB, sarpogrelate had a weaker anti-mitogenic effect in mesangial cells stimulated with 5-HT. Sarpogrelate was cytotoxic at concentrations over 10(-5) M according to the results of LDH release assays, and it reduced the S1 phase in mesangial cells stimulated with 5-HT by a flow cytometry. These findings suggest that sarpogrelate may be effective in the treatment of some glomerulonephritis associated with mesangial cell proliferation.

Change of xanthine dehydrogenase and xanthine oxidase activities in rat brain following complete ischaemia.

We studied the activities of xanthine dehydrogenase and xanthine oxidase in rat forebrain after complete ischaemia. Complete ischaemia was induced by decapitation after transcardiac infusion with saline. The activities of xanthine dehydrogenase and xanthine oxidase immediately after ischaemia were 93.3 +/- 38.7 and 18.8 +/- 7.7 microU/mg protein, respectively, and at 24 h after ischaemia were 183.5 +/- 75.1 and 60.8 +/- 15.2 microU/mg protein, respectively. The ratios of xanthine dehydrogenase/xanthine oxidase immediately and 24 h after ischaemia were 5.04 +/- 1.03 and 3.04 +/- 0.99, respectively. These data indicate that xanthine dehydrogenase and xanthine oxidase activities were maintained even 24 h after complete ischaemia. Conversion of xanthine dehydrogenase to xanthine oxidase proceeds slowly during complete ischaemia.

Mutational analysis within the 3' region of the PKD1 gene in Japanese families.

Autosomal dominant polycystic kidney disease (ADPKD) is a widespread genetic disease that causes renal failure. One of the genes that is responsible for this disease, PKD1, has been identified and characterized. Many mutations of the PKD1 gene have been identified in the Caucasian population. We investigated the occurrence of mutations in this gene in the Japanese population. We analyzed each exon in the 3' single copy region of the gene between exons 35 and 46 in genomic DNA obtained from 69 patients, using a PCR-based direct sequencing method. Four missense mutations (T3509M, G3559R, R3718Q, R3752W), one deletion mutation (11307del61bp) and one polymorphism (L3753L) were identified, and their presence confirmed by allele-specific oligonucleotide (ASO) hybridization. These were novel mutations, except for R3752W, and three of them were identified in more than two families. Mutation analysis of the PKD1 gene in the Japanese population is being reported for the first time.