人参皂甙Rg3对糖尿病肾病大鼠生化指标及病理的影响

目的:探讨人参皂苷Rg3对糖尿病肾病大鼠生化指标及病理改变的影响。方法:30只SD雄性大鼠按随机数字表法分为正常对照组、模型对照组和人参皂甙Rg3组。采用链脲佐菌素建立糖尿病肾病大鼠模型。造模成功后,Rg3治疗组每天以Rg3(0.5mg/kg)灌胃,余予以等量蒸馏水灌胃。30天后分别测3组大鼠血糖、24小时尿蛋白、血肌酐,并予以HE染色行肾组织活检。结果:与正常组比较,模型对照组大鼠血糖、24小时尿蛋白、血肌酐明显升高,肾小球体积增大,基底膜增厚、细膜基质增多,肾小球内炎细胞浸润(P0.01)。与模型对照组比较,人参皂甙Rg3组血糖、24小时尿蛋白、血肌酐明显降低,肾小球基底膜增厚程度减轻,细胞外基质堆积减少,差异具有显著性(P0.05)。结论:人参皂甙Rg3能显著降低糖尿病大鼠血糖、血肌酐、24 h尿蛋白,能改善其肾脏的病理损害。     

Early changes in renal function following chemically induced nephropathy

The functional changes in the rat kidney 24 h after administration of 2-bromoethanamine hydrobromide (BEA) have been extensively described. There is, however, little information regarding earlier alterations. The present study was designed to measure early changes in renal function in order to clarify further pathomechanisms of the BEA-induced lesion. Experiments were performed in two groups of Wistar rats with different infusion rates during the first 3 h following injection of 100 mg/kg BW BEA compared to sham-injected rats. Analysis included measuring urine flow, osmolality, urea, sodium and potassium as well as inulin and para-aminohippuric acid clearance. Our studies show a tubular as well as a glomerular involvement in BEA-induced nephropathy. A significantly higher urine flow occurred already in the first 30 min following injection of BEA. Urine osmolality began to decrease after 90 min, Na excretion was elevated at 3 h, K excretion was not significantly different from the control group, urea excretion was increased after 30 min. Contrary to other studies we found a continuously decreasing glomerular filtration rate and PAH clearance during the first 3 h. Our results suggest an early effect of BEA on tubular function (increasing sodium excretion), papillary concentration capacity (increasing urine flow combined with decreasing osmolality) and glomerular function (decreasing glomerular filtration rate).     

Gentamicin nephrotoxicity. II. Physiological, biochemical and morphological effects of prolonged administration to rats.

The purpose of this investigation was to determine the morphological, physiological and biochemical effects of gentamicin upon the rat kidney following prolonged administration of the antibiotic. Sprague-Dawley and Fischer 344 strain rats were given 3, 10, 20 or 40 mg gentamicin per kg body weight per day for 28 days. Morphologic alterations were evaluated by light and electron microscopy. Functional parameters included glomerular filtration rate, PAH secretion, renal plasma flow, sodium reabsorption, potassium excretion, urine volume and protein, and serum urea nitrogen. Oxidative metabolism of mitochondrial fractions from renal cortical homogenates was evaluated by oxygen uptake and P:O ratios. The results indicate focal proximal tubular injury, decreased tubular maximum secretion of PAH, and altered oxidative metabolism at the higher dose levels of gentamicin. Neither elevations of serum urea nitrogen nor alterations in glomerular filtration rate, renal plasma flow, or sodium or potassium excretion were observed. Thus, it appears that high dose levels (40 mg per kg per day) alter the structure and function of some proximal tubular segments when administered over prolonged periods. The alterations appear reversible. Although nephro-toxicity is identified under these conditions in rats, extrapolation to human patients usually receiving much lower doses must be guarded.     

Effect of prostaglandin inhibition on glomerular filtration rate in normal and uremic rabbits

Studies were performed to assess the effect of alterations in prostaglandin biosynthesis on glomerular filtration rate in rabbits with normal renal function and after surgical reduction of renal mass. In normal animals, the administration of either of two cyclo-oxygenase inhibitors resulted in a 53% reduction in urine prostaglandin E excretion, but no change in creatinine clearance. Creatinine clearance rates were almost 71% lower in the uremic animals when compared to the animals with normal renal function. Despite the reduction in renal mass, urine prostaglandin E excretion rates in the uremic animals were over twice that seen in normal rabbits. When factored by either glomerular filtration rate or remaining renal mass, urine prostaglandin E excretion rates in uremic rabbits when compared to normal animals were increased more than 9-times and 4-times respectively. Administration of cyclo-oxygenase inhibitors in the uremic animals resulted in a 71% decrease in urine prostaglandin E excretion and, unlike the non-uremic animals, a 53% fall in creatinine clearance. These findings suggest that intact renal prostaglandin biosynthesis is a necessary factor in the homeostatic adaptive mechanisms which maintain the glomerular filtration rate in animals with decreased renal mass.     

STZ诱导糖尿病肾病大鼠模型的建立

目的建立糖尿病大鼠动物模型,探讨其肾脏损害规律。方法用STZ65mg/kg一次性腹腔内注射方式制作糖尿病大鼠模型,设立空白对照组,饲养14周,期间观察大鼠血糖、尿糖及一般情况变化,实验结束时测定血肌酐、尿素氮、尿蛋白、尿白蛋白排泄率,取肾作病理及超微病理检查。结果模型组大鼠出现血肌酐、尿素氮、尿蛋白、尿白蛋白明显升高,出现肾脏肥大,病理显示明显的肾小球、肾小管病变。结论STZ诱导糖尿病大鼠肾脏表现肾小球及小管间质损害,可以用作糖尿病肾病研究的动物模型。     

Head-down tilt and restraint on renal function and glomerular dynamics in the rat

A model utilizing 25 degree head-down tilt (HDT) and incorporated with chronic catheterization and renal micropuncture techniques in rats was employed to study alterations in renal function induced by HDT. Renal function and extracellular volume measurements were performed after 24 h, 4 days, and 7 days of HDT in conscious rats and compared with their own control measurements and to nontilted but similarly restrained rats. After 24 h HDT, glomerular filtration rate (GFR) increased 19 +/- 8% and renal plasma flow (RPF) increased 18 +/- 8% with increases in urine flow rate, Na+, and K+ excretion in conscious rats. These increases after 24 h were associated with an increase in extracellular volume of 16 +/- 3% (P less than 0.01). In the nontilted controls, there was a decrease in extracellular volume after 24 h of suspension. After 7 days of HDT, GFR was decreased by 7 +/- 1% (P less than 0.01), but RPF and extracellular fluid volume were not different from control values. However, RPF and GFR increased in the nontilted rats after 7 days. After 7 days of HDT renal micropuncture studies demonstrated that single-nephron filtration rate was also decreased from 43 +/- 2 to 31 +/- 3 nl/min (P less than 0.05) due solely to reductions in the glomerular ultrafiltration coefficient (0.11 +/- 0.01 to 0.07 +/- 0.01 nl.s-1 X mmHg-1, P less than 0.05). There was a dissociation between GFR and water and Na+ excretion at days 4 and 7 of HDT not observed in the nontilt restraint controls.     

转化生长因子β1和snail1参与糖尿病大鼠肾小管上皮细胞向间充质细胞转变

本文旨在观察转化生长因子β1（transforming growth factor-β1,TGF-β1）和锌指转录因子Snail1在糖尿病（diabetes mellitus,DM）大鼠肾组织中的表达,并初步探讨它们与肾小管上皮细胞向间充质细胞转变的关系。链脲佐菌素（streptozotocin,STZ）诱发大鼠DM,按病程分为2、4、8、12、16、20、24周、16周胰岛素治疗（16wA）、20,周胰岛素治疗（20wA）和24周胰岛素治疗（24wA）组（n=6）。其中胰岛素治疗组动物从第13周起用胰岛素控制血糖至正常水平,每一时点均设鼠龄匹配的正常对照组。测定各组血糖、24h尿蛋白、血肌酐（serum creatinine,Scr）、肾脏指数。PAS染色光镜观察肾脏病理学改变。免疫组织化学检测肾脏Snail1、TGF-β1、α-平滑肌肌动蛋白（α-smooth muscle actin,α-SMA）、E-钙黏素和纤连蛋白（fibronectin,FN）的表达;Western blot检测肾皮质Snail1、TGF-β1和E-钙黏素蛋白表达。RT-PCR检测肾皮质Snail1和E-钙黏素mRNA表达。结果显示：（1）DM各组大鼠的血糖、24h尿蛋白、Scr、肾脏指数均较正常对照组明显升高（P〈0．05,P〈0．01）,胰岛素治疗组大鼠上述指标均较DM组显著降低（P〈0．01）。（2）TGF-β1和Snail1免疫组织化学阳性染色见于DM各组大鼠肾小管,正常对照组未见阳性表达,胰岛素治疗组大鼠弱阳性表达,并随治疗时间延长而减少。从16周开始在DM大鼠肾小管上皮细胞可见α-SMA蛋白阳性表达,胰岛素治疗组大鼠未见α-SMA蛋白表达;DM组大鼠E-钙黏素蛋白阳性染色明显少于正常对照组。（3）DM组大鼠肾皮质TGF-β1和Snail1蛋白以及Snail1 mRNA表达较正常对照组显著增高（P〈0．01）,胰岛素治疗组大鼠则显著低于DM组（P〈0．01）;DM组E-钙黏素mRNA和蛋白表达与TGF-β1和Snail1呈相反变化。结果提示,TGF-β1和Snail1可能参与DM大鼠肾小管上皮细胞向间充质细胞转变,胰岛素治疗可抑制两者表达并阻断肾小管上皮细胞向间充质细胞转变。     

Effects of experimental nephrosis on basement-membrane components and enzymes of collagen biosynthesis in rat kidney.

The aim of the present study was to find out whether the basement-membrane proteins laminin and type IV collagen are involved in the development of aminonucleoside-induced nephrosis. These proteins were measured by specific radioimmunoassays in serum, urine and kidney-cortex samples, and they were localized in the glomeruli by indirect immunofluorescence. Nephrosis was induced in rats with a single intraperitoneal injection of puromycin aminonucleoside. Serum laminin concentrations, detected by a radioimmunoassay for the P2 domain of the protein, increased to reach a maximum at days 5-7, and they remained elevated until at least day 14. The increase preceded the development of proteinuria, suggesting a role for laminin in glomerular function. Concomitant with proteinuria, increasing amounts of laminin antigenicity were also found in the urine. The size of the laminin antigen in serum was estimated by gel filtration, and the serum forms were found to contain both the P1 and the P2 regions of the intact laminin molecule. On the other hand, there were no changes in the serum or urinary concentrations of type-IV-collagen-derived antigens, as detected by a radioimmunoassay for the 7S collagen domain of this protein. The total content of laminin in kidney cortex, measured after digestion of the tissue with trypsin and collagenase, was, at day 9, still comparable with normal values, and the distribution of both basement-membrane proteins in the glomeruli, studied by indirect immunofluorescence, was similar to that in the controls. The tissue damage induced by aminonucleoside, however, seems to stimulate collagen biosynthesis, as the activities of prolyl 4-hydroxylase, lysyl hydroxylase and galactosylhydroxylysyl glucosyltransferase in kidney tissue increased significantly, with maxima at days 8-10.     

Renal metabolism and urinary excretion of platelet-activating factor in the rat

The origin of platelet-activating factor (PAF) in the urine remains ill defined. The present study documents that [3H]PAF (3.5 mu Ci) injected into the renal artery of isolated control rat kidney preparations perfused at constant pressure with a cell-free medium containing 1% bovine serum albumin (BSA) was excreted in negligible amounts (0.034%) in the urine, whereas 6% was retained by the kidney. When kidneys were perfused with a BSA-free medium, 0.029 and 71% of the total radioactivity added to the perfusate was recovered in the urine and in the renal tissue, respectively. [3H]PAF urine excretion in proteinuric kidneys from adriamycin-treated rats was still negligible (0.015%). Analysis of the renal tissue-retained radioactivity in control and proteinuric kidneys perfused with 1% BSA indicated metabolism into long chain acyl-sn-glycero-3-phosphorylcholine species, lyso-PAF, glycerols, and intact PAF. Thin layer chromatography analysis of [3H]glycerol fraction in these renal extracts showed two major components comigrating with 1-O-alkylglycerol and 1-O-alkyl-2-fatty acylglycerol. Isolated proximal tubules, but not glomeruli from nephrotic rats exposed to increasing concentrations of BSA (0-4%), had a higher PAF uptake than control tubules for BSA concentrations ranging from 0 to 0.1%. Our findings in the isolated perfused kidneys indicate that, in normal conditions, circulating PAF is excreted in the urine in negligible amounts and that the altered glomerular permeability to proteins does not affect this excretion rate. Moreover, analysis of renal tissue radioactivity documented that the renal metabolism of PAF is comparable in control and nephrotic kidneys.     

Role of dietary phosphorus in the progression of renal failure

Dietary phosphorus is thought to be a factor that impairs the residual renal function in patients with chronic renal failure. To determine the effect of dietary phosphorus on the prognosis of chronic renal failure, low-phosphorus milk was prepared from normal cow's milk using boehmite, a synthetic phosphate-ion absorbent. Regular diet, normal cow's milk, and low-phosphorus milk were then given to 5/6-nephrectomized rats and the serum levels of inorganic phosphorus, calcium, creatinine, and blood urine nitrogen in the rats in each group were compared. The serum levels of inorganic phosphorus and calcium were not different among the groups, despite a significant difference in phosphorus intakes. On the other hand, serum levels of creatinine (Cr) and blood urine nitrogen (BUN) in the rats fed low-phosphorus milk were significantly lower (Cr, 0.54+/-0.054mg/dl; BUN, 29.2+/-3.90mg/dl) than those in the rats fed a regular diet (Cr, 0.64+/-0.057mg/dl; BUN, 37.4+/-3.55mg/dl) or normal milk (Cr, 0.61+/-0.040mg/dl; BUN, 34.5+/-3.59mg/dl). No beneficial effect of protein restriction was observed when residual renal functions in rats fed a regular diet and those fed normal milk were compared. The results suggest that dietary phosphorus plays a major role in the progression of renal failure.     

Renoprotective effects of berberine and its possible molecular mechanisms in combination of high-fat diet and low-dose streptozotocin-induced diabetic rats

Berberine (BBR), an effective compound of Chinese traditional herbal medicine, has preventive effects on diabetes and its complications. In this study, we investigated the therapeutic effects and underlying molecular mechanisms of BBR in rats with high-fat diet and streptozotocin (STZ)-induced diabetic nephropathy model. BBR (50, 100, 200 mg/kg/d) were orally administered to male Sprague–Dawley rats after STZ injection and conducted for 8 weeks. Renal damage was evaluated by kidney weight to body weight ratio (KW/BW), urine microalbumin (UMAlb), urine protein for 24 h (UP24 h), urine creatinine (UCr), and histological examination. Type IV collagen and transforming growth factor-beta1 (TGF-β₁) were detected by immunohistochemistry and ultrastructure of glomeruli was observed. Fasting blood glucose (FBG),serum creatinine (SCr), blood urea nitrogen (BUN), total cholesterol (TC), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c) in serum and G protein-coupled receptor kinases (GRKs), cAMP in kidney were measured. Remarkable renal damage, hyperglycemia and hyperlipidemia were observed in DN rats. BBR could restore renal functional parameters, suppress alterations in histological and ultrastructural changes in the kidney tissues, improve glucose and lipid metabolism disorders, and increase cAMP levels compared with those of DN model group. Furthermore, BBR down-regulated total protein expression of GRK2, GRK3 and up-regulated expression of GRK6 of renal cortex in DN rats, but had a slight effects on GRK4 and GRK5. These studies demonstrate, for the first time, that BBR exerts renoprotection in high-fat diet and STZ-induced DN rats by modulating the proteins expression of GRKs in G protein- AC-cAMP signaling pathway.     

GH administration and renal IGF-I system in arthritic rats

Experimental arthritis in rats results in a growth failure and a decrease in circulating and hepatic concentrations of insulin-like growth factor I (IGF-I). Renal damage has also been reported in arthritic rats. The aim of this study was 1) to analyse if alterations in the IGF-I system in the kidney occurs in adjuvant-induced arthritis and 2) to analyse if recombinant human GH (rhGH) administration is able to reverse these effects. Male Wistar rats were injected with complete Freund's adjuvant or vehicle and 22 days later they were killed. Arthritis increased serum creatinine levels, relative kidney weight and IGF-I concentrations in this organ. In a second experiment, arthritic and control rats received rhGH (3 UI/Kg sc) or 250 microl saline from day 14, after adjuvant or vehicle injection, until day 22. IGF-I concentrations were higher in both the renal cortex and medulla of arthritic rats. In contrast, kidney IGF-I mRNA was lower in both areas of arthritic animals. GH treatment significantly decreased serum creatinine levels and IGF-I concentrations in the kidney cortex and medulla of arthritic rats. However, the administration of rhGH to arthritic animals significantly increased the IGF-I gene expression in both the renal cortex and medulla. Serum and kidney concentrations of IGF-I binding proteins (IGFBPs) were increased in arthritic animals and they were reduced by GH administration. CONCLUSION: These data suggest that experimental arthritis causes renal dysfunction and GH treatment can ameliorate this effect.     

山药多糖治疗肥胖糖尿病肾病大鼠的效果观察及对其肾功能和肠道微生态的影响

目的 观察山药多糖治疗肥胖糖尿病肾病大鼠的效果,并探讨其对肾功能、肠道微生态的影响。 方法 以高脂饮食、肾切除+腹腔注射STZ建立肥胖糖尿病肾病大鼠模型,分为5组,另取8只正常SD大鼠记为正常组。阳性药组予以10 mg/kg洛丁新灌胃,低剂量组、中剂量组和高剂量组分别予以50、100、200 mg/kg山药多糖灌胃,模型组与正常组均予以等量生理盐水灌胃,每天1次,共30 d。对比治疗前后体质量、尿蛋白、肾功能、肠道菌群变化。 结果 治疗后阳性药组和3剂量组体质量、尿蛋白、血清肌酐(Scr)、血清尿素氮(BUN)水平均下降,且均低于模型组,模型组则均高于正常组,差异均有统计学意义(P结论 山药多糖可减轻肥胖糖尿病肾病大鼠的体重,改善肾功能,还可调节肠道微生态,其作用呈剂量依赖性。     

Renal excretion of recombinant immunotoxins containing pseudomonas exotoxin

Recombinant immunotoxins BL22 (CAT-3888) and LMB-2, composed of Fv fragments of anti-CD22 and CD25 MAbs, respectively, have produced major responses in patients with hematologic malignancies, and are also associated with renal toxicity, particularly with BL22. Characterization of the renal excretion of recombinant immunotoxins, which have 2-4 h half-lives in plasma, has not been reported in humans. To study the renal excretion of recombinant immunotoxins, urine from patients treated with BL22 was collected and the recombinant protein visualized after trichloroacetic acid (TCA) precipitation or anion exchange chromatography. BL22 viewed by immunoblot was found in the urine of patients within 8 h after dosing as an intact protein, and progressively degraded to fragments of <20 kDa within 1 day. We studied the stability of BL22 and LMB-2 added to urine at different time points and pH. When exposed to urine ex vivo, BL22 time-dependent proteolysis was similar to that observed in treated patients. By N-terminal sequencing, proteolysis was documented at positions 348-349 and 350-351 of BL22, and 339-340 and 341-342 of LMB-2, and other proteolytic sites were observed as well. Our data suggest that BL22 is excreted into the urine in a potentially cytotoxic form, even after its plasma level declines, and may remain intact long enough to cause renal toxicity.     

Reduced urinary excretion of sulfated polysaccharides in diabetic rats

The aim of the present study was to further understand the changes in renal filtration that occur in the early stages of diabetes mellitus. Diabetes was induced in male Wistar rats by a single injection of streptozotocin. Glycemia, body weight, 24-h urine volume and urinary excretion of creatinine, protein and glycosaminoglycans were measured 10 and 30 days after diabetes induction. All the diabetic animals used in the present study were hyperglycemic, did not gain weight, and presented proteinuria and creatinine hyperfiltration. In contrast, the glycosaminoglycan excretion decreased. Dextran sulfates of different molecular weights (6.0 to 11.5 kDa) were administered to the diabetic rats, and to age-matched, sham-treated controls. Most of the dextran sulfate was excreted during the first 24 h, and the amounts excreted in the urine were inversely proportional to the dextran sulfate molecular weight for all groups. Nevertheless, diabetic rats excreted less and accumulated more dextran sulfate in kidney and liver, as compared to controls. These differences, which were observed only for the dextran sulfates of higher molecular weights (>7 kDa), increased with the duration of diabetes. Our findings suggest differential renal processing mechanisms for proteins and sulfated polysaccharides, with the possible involvement of kidney cells.     

Radioimmunological quantitation of the urinary trypsin inhibitor in normal blood and urine

A radioimmunoassay for measurement of the urinary trypsin inhibitor in human serum and urine is described. Because of the immunological cross-reactivity between the inter-alpha-trypsin inhibitor and the urinary trypsin inhibitor the plasma and serum were treated with perchloric acid to precipitate the inter-alpha-trypsin inhibitor. Gel filtration of serum before and after acid treatment showed identical peaks corresponding to the urinary trypsin inhibitor. The normal level of the urinary trypsin inhibitor in fresh plasma from 30 blood donors was 6.38 +/- 0.33 mg/l (SEM), and in sera from 24 healthy volunteers 7.14 +/- 0.27 mg/l (SEM). In urine from 23 healthy volunteers the normal excretion was 8.17 +/- 1.18 mg/24 h (SEM).     

Recovery of exocrine pancreas six months following pancreatitis induction with L-arginine in streptozotocin-diabetic rats.

The aim of the present work was to investigate the laboratory and morphologic alterations in the pancreas 6 months after pancreatitis induction with L-arginine (Arg) in normal and streptozotocin (STZ)-diabetic rats. The amylase content of the pancreas was significantly decreased in the Arg-treated groups vs. the control group. No significant changes were observed in the DNA, soluble protein and lipase contents of the pancreas. In the STZ-treated groups, the serum glucose level was significantly elevated, whereas the serum immunoreactive insulin (IRI) level was significantly decreased vs. the control group. In these treated groups, the amylase content of the pancreas was also significantly decreased, but that of trypsinogen was significantly elevated vs. the control group. Histologic sections revealed periductal fibroses, adipose tissue and tubular complexes in the Arg-treated rats, but centroacinar hyperplasia was not observed in these groups. No alterations were observed on histological examination in the diabetic rats vs. normal rats 6 months following pancreatitis induction. In conclusion, a major restitution of the pancreatic enzyme content, but moderate histologic alterations were detected 6 months following pancreatitis induction with Arg. The diabetic state appeared to shift the normal pancreatic enzyme content (decreased amylase and increased trypsinogen) in this long-term study, but not to modify the recovery of the exocrine pancreas 6 months following Arg-induced pancreatitis.     

Urinary concentrating defect in glutathione-depleted rats

The effect of an acute depletion of glutathione by diethyl maleate injection on renal concentrating function was examined in rats. The parameters tested were the concentration and dilution of urine, applying conventional clearance techniques. Tissue osmolality and Na+-K+ ATPase activity were also measured. Diethyl maleate treated rats showed a diminished renal glutathione concentration and an impairment in the glomerular filtration rate and in electrolyte and water excretion. Treated rats also showed a diminished urine-to-plasma osmolality ratio as compared with controls. The studies on free water formation revealed a marked difference between groups; these data were supported with a diminished medullary Na+-K+ ATPase and a diminished corticomedullary osmolality gradient in the treated rats. The studies suggest that one area of target cells of glutathione depletion is that of the ascending limb of Henle's loop.     

Characteristics of the action of cisplatin and cycloplatam on the rat kidney

On the 5th day after intraperitoneal injection of cisplatin the rats developed renal insufficiency. The concentration of creatinine and urea in blood serum increased 9-fold, the glomerular filtration rate decreased 7.7-fold, the weight of kidney increased by 44%. The content of tissue sodium was found to increase, while that of K to decrease. The intraperitoneal injections of cycloplatam (up to 25 mg/kg) induced in rats no renal insufficiency, the kidney weight and the ion and water content in the tissue did not change. In the experiments with cisplatin the Pt level in kidney reached 59.1 +/- 3.05 micrograms/g dry substance, after the injection of cycloplatam 25 mg/kg it was 104.9 +/- 2.95. No nephrotoxic action of cycloplatam may be due to the presence in the molecule of the cyclopentyl substitute.     

Increased urinary excretion of platelet activating factor in mice with lupus nephritis

Platelet activating factor (PAF) is present in urine from humans and experimental animals in normal conditions. Very little is known about changes in PAF urinary excretion under pathologic conditions and no data are available about the origin of PAF in the urine. In the present study we explored the possibility that immunologic renal disease is associated with an increase in PAF urinary excretion using gas chromatography-mass spectrometry technique. To clarify the renal or extrarenal origin of urinary PAF we evaluated whether exogenously administered PAF (1-[1', 2'-3H]alkyl) is filtered through the glomerulus and excreted in the urine. The results show that: 1) urine from mice with lupus nephritis in the early phase of the disease contained amounts of PAF comparable to those excreted in normal mouse urine, 2) PAF levels increased when animals started to develop high grade proteinuria, 3) after intravenous injection of [3H] PAF in nephritic mice, a negligible amount of [3H] ether lipid, corresponding to [3H]1-alkyl -2-acyl-3-phosphocholine (alkyl-2-acyl-GPC), was recovered from the 24 h urine extract.