Filtration Rate Of Kidney Research Articles

Preventing kidney failure in hemolytic anemias with a novel heme and hemoglobin scavenger

Chronic hemolytic conditions, seen in genetic and acquired hemolytic diseases, result in increased levels of circulatory hemoglobin (Hb) released from erythrocytes, free heme, and iron. Cell-free Hb's toxicity arises from the Hb dissociation into dimers that can traverse tissue barriers, impacting crucial compartments like arterial smooth muscle cells and renal glomeruli. Chronic hemolysis leads to vasoconstriction, renal injury, and activates pathways via Hb oxidation and heme-ligation of TLR4 on endothelial cells, as well as leukocytes, affecting adhesion pathways. Hb and heme exposure to the immune system causes phagocyte dysfunction, inflammation suppression, and impaired antigen presentation. Kidneys are particularly susceptible to Hb toxicity due to Hb and dimer penetration into glomeruli and tubules, disrupting filtration forces, elevating the glomerular filtration rate (GFR), and causing acute kidney injury (AKI). To combat this issue, our group developed a novel Hb and heme scavenger based on apohemoglobin-haptoglobin (apoHb-Hp), functioning as both a hemopexin (Hpx) and Hp mimetic to scavenge cell-free Hb and heme during hemolytic states. Our study utilized the dorsal window chamber model in Golden Syrian hamsters, employing FITC-Sinistrin for non-invasive GFR measurement, avoiding the need for blood and urine sampling throughout time to estimate GFR. Two experiments were conducted, volumetric exchange groups with 20% of the animal’s blood volume either with Hb at different concentrations or a combination ApoHb-Hp and Hb. Results showed a significant acute decrease of 35% in half-life of the Hb group at 1.2g/dL and 5g/dL after two hours, and further decrease is seen of 45% at 24hrs. In contrast, the ApoHb-Hp group experienced a 30% decrease at 2hrs but reverted back to baseline at 24hrs, signifying Hb's predominant effect on the acute decrease rather than the volume change. Furthermore, the ApoHb-Hp group demonstrated a quicker return to baseline compared to the Hb group after the 24-hour mark, suggesting prolonged Hb exposure's lasting impact on kidney filtration rate, potentially leading to irreversible damage. Further research is required to comprehend these findings fully and explore ApoHb-Hp's protective role in mitigating Hb-induced kidney damage. Title of the project: Bioengineering a Dual Function Protein Construct to Detoxify Heme and HemoglobinProject number: R01HL159862Title of the project: Bioengineering a novel therapeutic protein complex to minimize the effects of medical device induced hemolysis.Project number: R01HL162120. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Preventing Kidney Failure in Hemolytic Anemias with a Novel Heme and Hemoglobin Scavenger

Pathophysiological conditions characterized by chronic hemolysis, such as genetic and acquired hemolytic diseases, lead to increased levels of circulatory cell-free hemoglobin (fHb), free heme, and iron. The toxicity of free acellular hemoglobin has been a subject of intense study to understand its impact on the human body. fHb's small size allows it to extravasate into various organs, causing damage. The kidney is particularly vulnerable to Hb toxicity as it can filtrate through the kidneys, affecting glomerular filtration rate and leading to kidney failure. To address this, our group has developed a novel technique using the dorsal window chamber model in Golden Syrian hamsters. This method allows us to non-invasively measure glomerular filtration rate (GFR) using FITC-Sinistrin. The advantage of this approach is that it can assess renal function in awake animals, eliminating the need for anesthesia and minimizing its impact on the assessment. We also tested the function of ApoHb-Hp, a scavenger for Hb and heme, developed by our group, to see how it protects kidney function from mild and severe hemolysis. Our data involved two sets of experiments. In the first set, we injected groups with 10% of their blood volume, either with Hb alone or along with ApoHb-Hp. In the second set, we performed a 20% volumetric exchange of Hb or ApoHb-Hp with Hb. The results indicated that the group infused with Hb showed a sharp 60% decrease in half-life after 2 hours, but it returned to baseline after 24 hours. On the other hand, the group infused with ApoHb-Hp only showed a 30% decrease, suggesting that Hb is responsible for a more pronounced acute decrease, rather than just the volume change. Furthermore, when comparing the exchange data, both the Hb and ApoHb-Hp groups exhibited a 55% decrease in half-life after 2 hours compared to baseline, attributed to the change in volume. However, at the 24-hour mark, the ApoHb-Hp group returned to baseline, while the Hb group's half-life continued to decrease, reaching an 86% decrease compared to baseline. In conclusion, our preliminary data indicates that continuous exposure to Hb has a more prolonged effect on the kidney's filtration rate, potentially causing prolonged kidney impairment and irreversible damage. Further research is needed to understand the full implications of these findings and to explore the protective role of ApoHb-Hp in mitigating Hb-induced kidney damage.

Nutrition Disturbances and Metabolic Complications in Kidney Transplant Recipients: Etiology, Methods of Assessment and Prevention—A Review

Nutrition disturbances occur at all stages of chronic kidney disease and progress with the decrease of the kidney filtration rate. Kidney transplantation (KTx) as the best form of kidney replacement therapy poses various nutritional challenges. Prior to transplantation, recipients often present with mild to advanced nutrition disturbances. A functioning allograft not only relieves uremia, acidosis, and electrolyte disturbances, but also resumes other kidney functions such as erythropoietin production and vitamin D3 metabolism. KTx recipients represent a whole spectrum of undernutrition and obesity. Since following transplantation, patients are relieved of most dietary restrictions and appetite disturbances; they resume old nutrition habits that result in weight gain. The immunosuppressive regimen often predisposes them to dyslipidemia, glucose intolerance, and hypertension. Moreover, most recipients present with chronic kidney graft disease at long-term follow-ups, usually in stages G2-G3T. Therefore, the nutritional status of KTx patients requires careful monitoring. Appropriate dietary and lifestyle habits prevent nutrition disturbances and may improve kidney graft function. Despite many nutritional guidelines and recommendations targeted at chronic kidney disease, there are few targeted at KTx recipients. We aimed to provide a brief review of nutrition disturbances and known nutritional recommendations for kidney transplant recipients based on the current literature and dietary trends.

Successful application of Yoga Prana Vidya Protocols to normalize Kidney function: A case study of stage 2 kidney disease

Introduction: kidneys filter blood by removing waste and extra water to make urine. The kidney's filtration rate, called the glomerular filtration rate (GFR), shows how well the kidneys are filtering. Chronic Kidney Disease (CKD) is known to be the 6th fastest growing cause of death globally. Early detection of CKD can help to protect kidney function. This paper presents a case of Stage 2 Kidney disease treated successfully by the application of Yoga Prana Vidya healing protocols. Method: This study uses case study method, analysing patient medical records and YPV protocols used in treating the patient for 6 months. Patient feedback also obtained for analysis. Results: Improvements in the main parameters achieved at the end of 6 months of YPV intervention show that eGFR improved from 79 to 95. Total Cholesterol improved from 235 mg/dl to 165 mg/dl. HDL Cholesterol increased from 32 mg/dl to 47 mg/dl and LDL Cholesterol reduced from 150 mg/dl to 94 mg/dl. Patient achieved peace and satisfaction of YPV treatment that worked for normalizing his kidney condition. Conclusion: Using the YPV intervention for this patient, only YPV healing was given and no other form of therapy or treatment was given for stage 2 kidney ailment, which shows that YPV Healing System can be applied not only as complementary treatment but also as an alternative treatment mode in such cases of diseases. Further research may be conducted with wider applications of YPV Healing system to various other kidney ailments.

Abstract P042: Role Of Angiotensin In Determining Blood Flow Remaining Kidney Following Nephrectomy

We have previously presented data obtained in anesthetized Sprague Dawley (SD) rats showing acute increases of the renal blood flow (RBF) in the remaining kidney after unilateral nephrectomy (UNx) which were prevented with the AT1 receptor blocker losartan (ARB). We now chronically monitored RBF for 7 days following UNx in unanesthetized SD rats (6 weeks of age) with daily ARB treatment (oral; 10 mg/Kg; n=6) or vehicle (Vhe; Nutella; n=7) administered every 12 hr, from 5 days before UNx and throughout the entire experimental period. Rats were first instrumented with a Transonic flow probe on the left renal artery and a femoral arterial catheter for 24 hr continuous monitoring of RBF and mean arterial pressure (MAP). A week later, rats were anesthetized with isoflurane, and the right kidney was removed (UNx). After rapid recovery (15 min), RBF and MAP were monitored continuously for the next 7 days. In ARB treated rats, MAP fell an average of 115 to 106 mmHg (p<0.05) and RBF increased from 6.2 to 7.4 ml/min (p=0.06). Following Unx, RBF of both the ARB and Vhe group gradually rose (P<0.05) to an average of 10.6 and 9.9 ml/min (p=0.48) in ARB and Vhe treated groups respectively at day 7 while MAP remained unchanged. A similar increase of kidney weight was observed in both groups. Other SD rats (n=7) were instrumented with a femoral arterial and venous catheter for measurements of GFR following UNx. Rats were trained to wear a jacket carrying a miniaturized light emitting diode for real-time transcutanous excitation and detection of the emitted light to determine disappearance curves following i.v. injection of FITC-Sinistrin. Total GFR decreased from 1.8 to 1.2 ml/min/100gbw 2 days after UNx (p<0.05) and remained at that level for 21 days following UNx. We conclude that following UNx the RBF of the remaining kidney increases independent of changes of the renin-angiotensin system and corresponds to kidney hypertrophy. GFR returned to nearly 70% of the 2 kidney filtration rate 2 days following UNx and remained unchanged for the next 21 days.

Underreporting of chronic kidney disease according to laboratory criteria of Brazilian adults

Abstract Background This is the first study in Brazil that evaluates the prevalence of low renal function in the Brazilian population and associated factors, using biochemical measures. Methods This is a cross-sectional household-based epidemiological survey, the National Health Survey (PNS), conducted in 2014 and 2015. The explanatory variables were: sociodemographic characteristics, lifestyles, chronic diseases, anthropometry. The prevalence of kidney filtration rate (KFR) <60 ml / min / 1.73m2 was estimated, using Poisson regression to calculate the Prevalence Ratio Adjusted (RPaj) by age and gender. Results The prevalence of low renal function was 6.48% (95% CI 5.88-7.09). After adjusting remained associated: female (RPaj 1.4 CI (95% 1.16-1.68), age 45-59 years was RPaj = 7.3 (95% CI 3.8-14.1), 60 years or older RPaj = 33.6 (95% CI 17.8- 63.4), obesity RP 1.32 (95% CI 1.1-1.7), diabetes PR = 1.4 (95% CI 1.2-1.8), poor / very poor self-rated health PR = 1.5 (95% CI 1.2-1.9). Conclusions Renal function <60 ml / min / 1.73m2 was higher in females, increased with age, was associated with obesity, diabetes and poorer health assessment. CKD through biochemical tests and risk and protection factors are essential to support public health policies. Key messages The prevalence with laboratory data was 4 times higher than self-reported studies, showing the underreporting of low renal function in Brazil population. The primary care team should request simple biochemical tests, such as creatinine, routinely in the target population, especially the elderly, for prevention and early management of kidney diseases.

An Updated Review on the Role of Physical Activity and Nutrition in the Treatment of Renal Diseases

Kidney diseases are divided into two: acute and chronic sub-groups that lasted less and more than three months, respectively. Chronic Kidney Diseases which is known as CKD is a gradual kidney dysfunction that leads to End-Stage Renal Disease (ESRD), a condition that kidney stops to work properly and needs to be treated by transplant or dialysis. ESRD accompanies with reduced Glomerular Filtration Rate (GFR) that according to reduction of kidney filtration rate, it is classified into five stages. Kidney damages resulted in various direct and indirect dysfunctions, such as proteinuria, albuminuria, metabolic acidosis or even stroke, white matter diseases, intracerebral microbleeds and cognitive impairment.

Measuring Kidney Perfusion, pH, and Renal Clearance Consecutively Using MRI and Multispectral Optoacoustic Tomography

Purpose: To establish multi-modal imaging for the assessment of kidney pH, perfusion, and clearance rate using magnetic resonance imaging (MRI) and multispectral optoacoustic tomography (MSOT) in healthy mice. Kidney pH and perfusion values were measured on a pixel-by-pixel basis using the MRI acidoCEST and FAIR-EPI methods. Kidney filtration rate was measured by analyzing the renal clearance rate of IRdye 800 using MSOT. To test the effect of one imaging method on the other, a set of 3 animals were imaged with MSOT followed by MRI, and a second set of 3 animals were imaged with MRI followed by MSOT. In a subsequent study, the reproducibility of pH, perfusion, and renal clearance measurements were tested by imaging 4 animals twice, separated by 4 days. The contrast agents used for acidoCEST based pH measurements influenced the results of MSOT. Specifically, the exponential decay time from the kidney cortex, as measured by MSOT, was significantly altered when MRI was performed prior to MSOT. However, no significant difference in the cortex to pelvis area under the curve (AUC) was noted. When the order of experiments was reversed, no significant differences were noted in the pH or perfusion values. Reproducibility measurements demonstrated similar pH and cortex to pelvis AUC; however, perfusion values were significantly different with the cortex values being higher and the pelvic values being lower in the second imaging time. We demonstrate that using a combination of MRI and MSOT, physiological measurements of pH, blood flow, and clearance rates can be measured in the mouse kidney in the same imaging session.

Acute kidney injury

Acute kidney injury (AKI) is defined as an abrupt decline in kidney filtration rate. It is characterised by increased serum/plasma creatinine concentration and changes in urine output. This article reviews the physiology, current veterinary grading systems and common causes of AKI. Nurses should be aware of how to undertake the procedures required for the diagnosis of AKI and how to deliver nursing care to affected hospitalised patients. Patients affected by AKI can achieve complete recovery and effective nursing is key in maximising the prognosis of these patients.

Bioremediation of cadmium induced renal toxicity in Rattus norvegicus by medicinal plant Catharanthus roseus.

Cadmium is the second most hazardous metals with bio-concentration factor (BCF) > 100 Although WHO permitted cadmium concentration in drinking water is 0.005 mg/L, yet the reality is far above to this limit because of industrial utility of this metal. Oral exposure of cadmium to human results in dreadful symptoms of metabolic disorders especially in liver and kidneys. Endogenous protection could be supported by some exogenous herbal supplement (viz., Catharanthus roseus in this case) to overcome the toxic effects. Present Study has been designed to find out the functional renal changes under the effect of cadmium and Catharanthus roseus in the model organism albino rats. Cadmium significantly (p > 0.01) increases the level of nitrogenous waste (Urea, BUN, Uric Acid and Creatinin), while decreases the serum protein profile in acute and sub-acute sets. Urea concentration of control ranged from 16.56 to 17.72 mg/dl while that of Group-B and D were 19.84 to 20.87 mg/dl and 17.56 to 17.59 mg/dl respectively. Similarly uric acid concentration ranged in control form 6.98 to 8.01 mg/dl in group-B from 7.58 to 10.25 mg/dl, in Group-D 8.02 to 8.59 mg/dl respectively. Creatinin concentration ranged in control 0.57 to 0.65 mg/dl, in group-B 0.97 to 1.02 mg/dl, in group-D – 0.95 to 0.98 mg/dl respectively.These results might be due to altered filtration rate of kidney because of protein disruption. The studies conclude the efficient nephro-protection offered by Catharanthus roseus extract against Cadmium toxicity.

A Practical Design and Implementation of a Low-Cost Platform for Real-Time Diagnostic Imaging

The emerging need for the current medical devices to achieve immediate visualization and performing diagnostic imaging at real time augurs the demand for high computational power of the associated electronic circuitry. The demand for such a high computational requirement is often met by using software methods to accelerate the computation, which is possible only to a certain extent, impairing the feasibility of real-time imaging and diagnosis. In this paper, a new method of using digital signal processors (DSPs) with a specialized pipelined vision processor (PVP) embedded at the hardware level to accelerate the routinely time-consuming imaging computation is proposed and validated. A lab prototype is built for the feasibility study and clinical validation of the proposed technique. This unique architecture of the PVP in a dual-core DSP offers a high-performance accelerated framework along with its large on-chip memory resources, and reduced bandwidth requirement provides as an ideal architecture for reliable medical computational needs. We have taken two sets sample studies from SPECT for validation—27 cases of thyroid medical history and 20 cases of glomerular filtration rate of kidneys. The results were compared with definitive post-scan SIEMENS image analysis software. From the statistical results, it is clearly shown that this method achieved very superior accuracy and 250% acceleration of computational speed.

Fetal hemoglobin induces changes to the glomerular filtration rate in kidney that resembles symptoms observed during preeclampsia and was ameliorated by co-administration of alpha-1 microglobulin.

Fetal hemoglobin induces changes to the glomerular filtration rate in kidney that resembles symptoms observed during preeclampsia and was ameliorated by co-administration of alpha-1 microglobulin.

Midterm outcomes of protection for upper urinary tract function by augmentation enterocystoplasty in patients with neurogenic bladder

To evaluate the midterm outcomes of protection for upper urinary tract (UUT) function by augmentation enterocystoplasty (AE) using a grading system for upper urinary tract dilation (UUTD) and a descriptive system for all urinary tract dysfunction (AUTD) in patients with neurogenic bladder. We retrospectively reviewed 120 cases of AE from our database, which was collected between 2005 and 2013. UUTD grading system was developed by magnetic resonance urography (MRU), and AUTD system was described by video-urodynamics, MRU, isotope renography, etc. UUT function was evaluated by these systems before operation, and at 6, 12, 24 and 36 months postoperatively. The indication, midterm outcomes and complications were evaluated. All patients had significant improvement for urodynamic parameters at 6 months postoperatively. Comparing the grades of UUTD and vesicoureteral reflux (VUR) before and after operation, the median grade of 95 UUTD ureters decreased from 3 to 0, and the percentage of 0 grade UUTD increased from 0 to 90.9 % at 36 months. The median grade of 96 VUR ureters decreased from 3 to 0, and the percentage of 0 grade VUR increased from 0 to 98.6 % at 36 months. The glomerular filtration rate of kidneys and serum creatinine level of patients had an increasing improvement after surgery. The midterm follow-up using UUTD and AUTD systems indicates that AE is effective and safe for UUT protection. The patients with moderate and severe UUT deteriorations and renal function impairment resulting from VUR and UUTD have undergone the increasing improvement.

Objective sleep, a novel risk factor for alterations in kidney function: the CARDIA study

ObjectiveTo determine the association between objectively measured sleep and 10-year changes in estimated glomerular filtration rate (eGFR). MethodsFrom 2003 to 2005, an ancillary sleep study was conducted at the Chicago site of the Coronary Artery Risk Development in Young Adults (CARDIA) study. Community-based black and white adults (aged 32–51 years) wore a wrist actigraph for up to six nights to record sleep duration and fragmentation. Sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI). Participants without history of cardiovascular or chronic kidney diseases, proteinuria, or hypertension at the 2000–2001 CARDIA examination were followed over 10 years (n = 463). eGFR was estimated from serum creatinine (eGFRCr) at the 2000–2001, 2005–2006, and 2010–2011 CARDIA examinations, whereas cystatin-C-estimated eGFR (eGFRCys) was measured at the 2000–2001 and 2005–2006 examinations. Generalized estimating equation regression and linear models estimated the associations of each sleep parameter with changes in eGFRCr and eGFRCys, controlling for cardiovascular and renal risk. ResultsSleep parameters were not related to 5-year change in eGFRCys. However, each 1 h decrease in sleep duration was significantly associated with a 1.5 mL/min/1.73 m2 higher eGFRCr [95% confidence interval (CI), 0.2–2.7], and each one-point increase in PSQI was significantly associated with a 0.5 mL/min/1.73 m2 higher eGFRCr (95% CI, 0.04–0.9) over 10 years. ConclusionIn this community-based sample, shorter sleep and poorer sleep quality were related to higher kidney filtration rates over 10 years.

Effects on kidney filtration rate by agmatine requires activation of ryanodine channels for nitric oxide generation

Agmatine, decarboxylated arginine, is produced in the kidney and can increase nephron and kidney filtration rate via renal vasodilatation and increases in plasma flow. This increase in filtration rate after agmatine is prevented by administration of nitric oxide synthase (NOS) inhibitors. In endothelial cells, agmatine-stimulated nitrite production is accompanied by induction of cytosolic calcium. NOS activity requires calcium for activation; however, the source of this calcium remains unknown. Ryanodine receptor (RyR) calcium-activated calcium release channels are present in the kidney cortex, and we evaluated if RyR contributes to the agmatine response. Agmatine microperfused into Bowman's space reversibly increases nephron filtration rate (SNGFR) by approximately 30%. cADP-ribose (cADPR) regulates RyR channel activity. Concurrent infusion of agmatine with the cADPR blocker 8-bromo-cADPR (2 microM) prevents the increase in filtration rate. Furthermore, direct activation of the RyR channel with ryanodine at agonist concentrations (5 microM) increases SNGFR, and, like agmatine, this increase is prevented by administration of N(G)-monomethyl-l-arginine, a nonselective NOS blocker. We demonstrate that agmatine does not elicit ADPR cyclase activity in vascular smooth muscle membranes and does not directly affect RyR calcium channel responses using sea urchin egg homogenates. These results imply interplay between endothelial cell cADPR/RyR/Ca(2+)/NO and the cADPR/RyR/Ca(2+) pathways in vascular smooth muscle cells in arterioles in the regulation of kidney filtration rate. In conclusion, we show that agmatine-induced effects require activation of cADPR and RyR calcium release channels for NO generation, vasodilation, and increased filtration rate.

Renal effects of glucagon-like peptide in rats

The present study examined the effects of recombinant glucagon-like peptide-1-(7-36)amide (rGLP-1) on renal hemodynamics and excretory function in innervated and denervated kidneys of anesthetized rats. Intravenous infusion of rGLP-1 at a dose of 1 μg·kg −1·min −1 increased urine flow and Na + excretion 13-fold in the innervated kidney. The natriuretic and diuretic response to rGLP-1 was attenuated in the denervated kidney in which urine flow and Na + excretion only increased 3-fold. Fractional excretion of Li +, an index of proximal tubular reabsorption, increased 219% in the innervated kidney but only 54% in the denervated kidney during infusion of rGLP-1. The diuretic and natriuretic response to rGLP-1 was associated with an increase in glomerular filtration rate (39%) in the innervated kidney, but it had no effect on glomerular filtration rate in the denervated kidney. These results indicate that the natriuretic and diuretic effects of rGLP-1 are due to inhibition of Na + reabsorption in the proximal tubule. It also increases glomerular filtration rate in kidneys with an intact renal innervation.

Production and clinical development of a Hansenula polymorpha-derived PEGylated hirudin.

This article describes the expression of the hirudin gene heterologously in the methylotrophic yeast Hansenula polymorpha, the establishment of an industrial-scale production process and the subsequent clinical development of polyethylene glycol (PEG)-hirudin. PEGylation increases the molecular weight of hirudin, thereby reducing its kidney filtration rate and immunogenicity and increasing its half-life in the circulation.

5335660 Magnetic resonance method of measuring kidney filtration rates

5335660 Magnetic resonance method of measuring kidney filtration rates

A comprehensive analysis of renal DTPA studies. III. Renal artery stenosis.

Renal DTPA studies were analysed to produce numerical data of renal function (blood flow, glomerular filtration, and excretion), and this was used as an adjunct to the routine imaging information in a study of renal artery stenosis (RAS). The results show an overall accuracy of 81%, with a sensitivity of 96% and a specificity of 61%. In patients with RAS, beta-blocking drugs reduced the difference between the two kidneys. ACE-inhibiting drugs appeared to preserve renal blood flow but also to cause a deterioration in the glomerular filtration rate of kidneys with RAS. An explanation is proposed, in which renal capillary pressure is more important for function than is renal blood flow.

Reduced renal blood flow in early cisplatin-induced acute renal failure in the rat.

Studies were designed to determine the cause of the reduced glomerular filtration rate (GFR) in early cisplatin-induced acute renal failure. Rats were studied 72 h following a single intraperitoneal injection of cisplatin (5 mg/kg) or vehicle (0.9% NaCl). Whole kidney GFR and blood flow were lower in cisplatin-treated animals than in controls (0.30 +/- 0.06 vs. 1.17 +/- 0.06 ml X min-1 X g kidney wt-1 and 5.30 +/- 0.62 vs. 8.25 +/- 0.43 ml X min-1 X g kidney wt-1, respectively; P less than 0.001), as were superficial nephron GFR and stop-flow pressure (20.2 +/- 2.1 vs. 34.5 +/- 2.0 nl X min-1 X g kidney wt-1 and 29.0 +/- 1.9 vs. 39.8 +/- 1.3 mmHg, respectively; P less than 0.001). After volume expansion, renal plasma flow increased in control rats, whereas whole kidney and single nephron GFR did not change. In experimental animals, whole kidney filtration rate rose to 0.58 +/- 0.07 ml X min-1 X g kidney wt-1, single nephron filtration rate increased to 29.9 +/- 3.5 nl X min-1 X g kidney wt-1 (P less than 0.005), and renal plasma flow increased to 5.62 +/- 0.60 ml X min-1 X g kidney wt-1 (P less than 0.05). Intratubular hydrostatic pressure was not different in the two groups before or after volume expansion. The results of these studies show that the reduced GFR in early cisplatin-induced renal failure is due, in part, to reversible changes in renal blood flow and renal vascular resistance.