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1.
OBJECTIVE: To identify the generation of the superoxide anion by equine spermatozoa. SAMPLE POPULATION: Multiple ejaculates collected from 3 Thoroughbred stallions. PROCEDURES: Induced superoxide production by reduced nicotinamide adenine dinucleotides (NAD[P]H; ie, reduced nicotinamide adenine dinucleotide [NADH] and reduced nicotinamide adenine dinucleotide phosphate [NADPH]) was measured by use of a nitroblue tetrazolium (NBT) reduction assay on whole spermatozoa and a cytochrome c reduction assay on isolated membrane fractions of spermatozoa. Localization of superoxide generation was determined by use of NBT cytochemistry. RESULTS: A dose-dependent increase in NBT reduction was found in the presence of NADPH, which was inhibited by superoxide dismutase (SOD). The flavoprotein inhibitor, diphenyleneiodonium (DPI; 5 or 15 microM), significantly decreased NBT reduction. Cytochrome c reduction by plasma membranes of spermatozoa was significantly higher in the presence of NADPH than in its absence. Cytochemical staining of equine spermatozoa in the presence of NADPH and NADH revealed diaphorase labeling in the spermatozoon midpiece and head. This staining was inhibited by DPI and SOD. CONCLUSIONS AND CLINICAL RELEVANCE: Results of our study indicate that superoxide generation is associated with a membrane-associated NAD(P)H oxidase present in equine spermatozoa, although mitochondrial generation of superoxide is also detected. This oxidase may play a role in cell signaling or may also contribute to cytopathic effects associated with oxidative stress in equine spermatozoa.  相似文献   

2.
Respiratory burst is due to the activation of a membrane bound NADPH oxidase induced by perturbation of the plasma membrane during phagocytosis or following interaction between the cell surface and a number of environmental stimuli. It refers to the increase in the non-mitochondrial O2 consumption with a concomitant production of different reactive species (superoxide anion, hydrogen peroxide, hydroxyl radical, singlet oxygen ...). The effects of the respiratory burst depend on the intensity and combination of the different actions which are defensive, toxic, activatory and modulatory of the inflammatory process.  相似文献   

3.
E-cadherin is a cell adhesion molecule that plays an important role in maintaining renal epithelial polarity and integrity. The purpose of this study was to determine the exact cellular localization of E-cadherin in pig kidney. Kidney tissues from pigs were processed for light and electron microscopy immunocytochemistry, and immunoblot analysis. E-cadhedrin bands of the same size were detected by immunoblot of samples from rat and pig kidneys. In pig kidney, strong E-cadherin expression was observed in the basolateral plasma membrane of the tubular epithelial cells. E-cadherin immunolabeling was not detected in glomeruli or blood vessels of pig kidney. Double-labeling results demonstrated that E-cadherin was expressed in the calbindin D28k-positive distal convoluted tubule and H+-ATPase-positive collecting duct, but not in the aquaporin 1-positive, N-cadherin-positive proximal tubule. In contrast to rat, E-cadherin immunoreactivity was not expressed at detectable levels in the Tamm-Horsfall protein-positive thick ascending limb of pig kidney. Immunoelectron microscopy confirmed that E-cadherin was localized in both the lateral membranes and basal infoldings of the collecting duct. These results suggest that E-cadherin may be a critical adhesion molecule in the distal convoluted tubule and collecting duct cells of pig kidney.  相似文献   

4.
The underlying pathophysiological triggers for equine acute laminitis are unknown, although digital vasoconstriction, ischaemia, hypoxia and reperfusion injury may be involved. The contractile responses of isolated equine digital arteries (EDAs), harvested from the hindlimbs of normal horses postmortem at an abattoir, were studied acutely (up to 3 h) under hyperoxic (95% oxygen, 5% CO2) and hypoxic (95% nitrogen, 5% CO2) conditions in organ baths. Phenylephrine (PHE; 10?6 m ), 5‐hydroxytryptamine (5‐HT; 10?7 m ) and high potassium (K+; 118 mm ) caused contraction in EDAs which was significantly (P < 0.0001) enhanced under hypoxic conditions. In contrast, contraction stimulated by 9,11‐dideoxy‐9α,11α‐epoxymethanoprostaglandin F2α (U44069; 3 × 10?8 m ) was not significantly enhanced by hypoxia (P = 0.75). Hypoxia‐enhanced contraction in response to K+ was greater (P < 0.03) in vessels with a functional endothelium than in vessels in which the endothelium was removed by rubbing. Fasudil (10?6 to 10?5 m ), a Rho kinase inhibitor, and apocynin (10?3 to 3 × 10?3 m ), an NADPH oxidase inhibitor, significantly (P ≤ 0.05) inhibited hypoxia‐enhanced contraction in response to PHE and 5‐HT. In conclusion, hypoxia‐enhanced contraction occurred in EDAs. This appears to be partially mediated by reactive oxygen species produced by NAPDH oxidase, which activate Rho kinase to increase calcium sensitisation and enhance smooth muscle contraction.  相似文献   

5.
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6.
A novel angiotensin‐converting enzyme (ACE) inhibitory peptide was isolated and purified from chicken bone extract by enzymatic digestion. The peptide was defined as an ACE inhibitor, and it demonstrated antihypertensive activity following oral administration to spontaneously hypertensive rats (SHRs). The results of this study suggest that peptides derived from an extract of chicken bones, administered orally, have the ability to reduce the blood pressure of SHRs significantly over a short period of time (3 h). Moreover, the blood pressure then remains low for 3 h. This peptide derived from chicken bones may therefore have great value as a short‐term remedy for chronic conditions such as high blood pressure. The amino acid sequence of the peptide was YYRA (Tyr‐Tyr‐Arg‐Ala), which was the origin of the Ig heavy chain V region (27–30 position). The IC50 value of its synthetic peptide was 33.9 μg/mL. We suggest that the ACE inhibitory and antihypertensive peptides derived from chicken bone extract may contribute to develop physiologically functional foods or improve food functionality.  相似文献   

7.
双峰驼肾近曲小管和远曲小管的体视学研究   总被引：1，自引：0，他引：1  
应用光镜和电镜技术,测算了双峰驼肾近曲小管和远曲小管微细结构的体视学参数,并与黄牛进行了比较.结果显示,双峰驼肾近曲小管刷状缘体积、微绒毛表面积、吞饮小泡和溶酶体体积均显著大于黄牛;远曲小管上皮细胞的线粒体体密度、侧基底面质膜面密度和周界长度也明显大于黄牛.这些结构的差异表明,双峰驼肾脏重吸收水分的能力更强大.  相似文献   

8.
An experiment was conducted to assess the relative in vivo and in vitro activities of chicken LH-RH-I and -II in laying, incubating and out-of-lay turkey hens. The highest plasma concentrations of LH were measured in laying turkey hens, whereas hypophyseal concentrations were highest in incubating hens (I) and lowest in the laying hens at the end of the laying period (EL). Hypophyseal and plasma concentrations of LH decreased with aging in laying hens (L) and the greater decrease occurred in the hypophyses. An in vitro hypophyseal acute challenge with 2-min pulses of cLHRH I or II (10−7 M) using a perifusion technique resulted in an increase in the release of LH in out-of-lay (OL) and incubating (I) hens, but not in laying (L) hens. Although both peptides elicited comparable responses in I hens, cLHRH II was more effective in OL hens. This difference was attributable to a greater amplitude of the response, whose duration was unchanged. Hypophyseal desensitization to a subsequent stimulation was observed in OL hens when the interval between stimulations was 30 min, but this did not occur at 60- or 120-min intervals. In vivo, the injection of cLHRH I or II, at doses of 10−8 and 10−10M/kg B.W. stimulated increases in the plasma concentrations of LH, which were initiated within 1 min of injection in OL and I hens but from 5 to 20 min postinjection in L hens. The responses were dose-related and greater immediate responses were measured with cLHRH I than with cLHRH II. Also, after the injection of cLHRH II at the 10−8 M/kg B.W. dose, the shape of the LH response consisted of an initial increase, followed by a more sustained phase during which LH concentrations were either stable (I hens) or continued to increase (L and OL hens) from 20 to 60 min after injection. In contrast, the injection of cLHRH I at doses of 10−8 or 10−10 M/kg or cLHRH II at a dose of 10−10 M/kg in I and OL hens, produced a peak of LH concentrations in plasma within 5 min and thereafter declined gradually. The difference in the in vivo responses to LHRH I and II could not be attributed to a greater potency of cLHRH II, but to a more prolonged action. In summary, the responses to both forms of chicken LH-RH varies markedly with the stage of the reproductive cycle (L, I, and OL) and differs between the in vivo and in vitro situations. Although cLHRH II may be more active than cLHRH I, controversy still surrounds its precise physiological role.  相似文献   

9.
Megalin, retinol-binding protein (RBP) and Tamm–Horsfall glycoprotein (THP) are involved in the renal metabolism of vitamin A in canine species. The presence of megalin, RBP and THP in the kidneys of dogs was investigated using immunohistochemical methods. Megalin was highly expressed in the apical membrane of the proximal convoluted and straight tubule cells. Immunoreactive RBP was detected below the apical plasma membrane, as well as in basolateral granules of the proximal convoluted tubule cells. THP immunoreactivity was seen in the epithelial cells lining the thick ascending limb of the loop of Henle. Furthermore, THP was displayed in a scattered pattern within the distal convoluted tubules. The co-localization of megalin and RBP coincides with biochemical studies that have shown megalin to be responsible for renal RBP absorption in the proximal convoluted tubules after filtration through the renal glomerulus. The presence of THP, the carrier for vitamin A in canine urine, showed that vitamin A excretion in the urine of dogs is not merely a filtration process but also seems to be a pathway located in the distal part of the nephron.  相似文献   

10.
It has been reported that cardiac chymase has an effect on cardiac fibrosis through the Angiotensin (Ang) II formation and an Ang II-independent mechanism. In the present study, Ang II type 1 (AT1) receptor blocker (candesartan cilexetil) was administered to dilated cardiomyopathic (DCM; Bio TO2) hamsters for 4 weeks to study the effect of AT1 receptor blocker on cardiac chymase-like activity and cardiac fibrosis. Echocardiography, histological examination, and assessment of cardiac angiotensin-converting enzyme (ACE)/chymase-like activities were conducted. Hamsters showed cardiac dysfunction due to increased left ventricular dimensions and decreased ventricular wall thickness, significant increase in cardiac chymase-like activity, and fibrosis. This result indicates that the cardiac chymase-like activity is responsible for cardiac fibrosis. When candesartan cilexetil was administered to Bio TO2 hamsters, cardiac chymase-like activity increased significantly, whereas cardiac fibrosis decreased significantly. Cardiac ACE and chymase-like activities were unchanged in non-DCM hamsters with candesartan cilexetil. This suggests that the cardiac Ang II formation mechanism was stimulated by suppressing the effect of cardiac Ang II, and cardiac chymase-like activity could be increased. Moreover, this mechanism may be more highly activated if cardiac Ang II is activated in the heart. In conclusion, we demonstrated that AT1 receptor blocker reduced cardiac fibrosis, although cardiac chymase-like activity increased. Because the Ang II-forming pathway and the effect of chymase in hamsters is similar to that in dogs, the results of the present study may supplement the available information for dogs.  相似文献   

11.
Numerous attempts have been made to develop angiotensin I converting enzyme (ACE) inhibitors from various sources of food protein. Generally chicken leg bones are discarded after industrial chicken meat processing without any substantial benefit. In previous studies, chicken leg bone proteins were hydrolyzed by various enzymes and the results demonstrated that Alcalase hydrolysates have considerable ACE inhibiting activities. In this study, the best ACE inhibitory hydrolysate (A4) (which was derived from chicken leg bone protein by Alcalase after 4 h incubation) was orally administrated (50 mg/kg bw) in spontaneously hypertensive rats (SHRs) to investigate its antihypertensive effects. After oral administration of A4, a maximal reduction activity of about 26 mmHg was found at 4 h and maintained to 8 h. Moreover, SHRs treated with A4 (50 mg/kg bw/day) for eight weeks exhibited a reduction in systolic blood pressure, which is as significant as the effects of Captopril ( P  < 0.05). These results suggested that chicken leg bones have a high potential for utilization to develop ACE inhibitors as potential food ingredients intended to alleviate hypertension.  相似文献   

12.
Two experiments (EXP) were conducted to test the hypothesis that porcine leptin affects GH, insulin-like growth factor-I (IGF-I), insulin, thyroxine (T4) secretion, and feed intake. In EXP I, prepuberal gilts received intracerebroventricular (ICV) leptin injections. Blood was collected every 15 min for 4 hr before and 3 hr after ICV injections of 0.9% saline (S; n = 3), 10 μg (n = 4), 50 μg (n = 4), or 100 μg (n = 4) of leptin in S. Pigs were fed each day at 0800 and 1700 hr over a 2-wk period before the EXP. On the day of the EXP, pigs were fed at 0800 hr and blood sampling started at 0900 h. After the last sample was collected, feeders were placed in all pens. Feed intake was monitored at 4, 20, and 44 hr after feed presentation. In EXP II, pituitary cells from prepuberal gilts were studied in primary culture to determine if leptin affects GH secretion at the level of the pituitary. On Day 4 of culture, 105 cells/well were challenged with 10−12, 10−10, 10−8, or 10−6 M [Ala15]-h growth hormone-releasing factor-(1-29)NH2 (GRF), 10−14, 10−13, 10−12, 10−11, 10−10, 10−9, 10−8, 10−7, or 10−6 M leptin individually or in combinations with 10−8 and 10−6 M GRF. Secreted GH was measured at 4 hr after treatment. In EXP I, before injection, serum GH concentrations were similar. Serum GH concentrations increased (P < 0.01) after injection of 10 μg (21 ± 1 ng/ml), 50 μg (9 ± 1 ng/ml), and 100 μg (13 ± 1 ng/ml) of leptin compared with S (1 ± 2 ng/ml) treated pigs. The GH response to leptin was greater (P < 0.001) in 10 μg than 50 or 100 μg leptin-treated pigs. By 20 hr the 10, 50, and 100 μg doses of leptin reduced feed intake by 53% (P < 0.08), 76%, and 90% (P < 0.05), respectively, compared with S pigs. Serum IGF-I, insulin, T4, glucose, and free fatty acids were unaffected by leptin treatment. In EXP II, relative to control (31 ± 2 ng/well), 10−10, 10−8, and 10−6 M GRF increased (P < 0.01) GH secretion by 131%, 156%, and 170%, respectively. Only 10−6 M and 10−7 M leptin increased (P < 0.01) GH secretion. Addition of 10−11 and 10−9 M leptin in combination with 10−6 M GRF or 10−11 M leptin in combination with 10−8 M GRF-suppressed (P < 0.05) GH secretion. These results indicate that leptin modulates GH secretion and, as shown in other species, leptin suppressed feed intake in the pig.  相似文献   

13.
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14.
LaBranche, T. P., Ehrich, M. F., Eyre, P. Characterization of bovine neutrophil β2‐adrenergic receptor function. J. vet. Pharmacol. Therap. doi: 10.1111/j.1365‐2885.2009.01143.x. This study compares bovine leukocyte β‐adrenergic receptor densities to that of the rat, demonstrates for the first time a functional β2‐adrenergic receptor signaling pathway in steer neutrophils, and investigates the effect of an inflammatory stimulus on that signaling pathway. The β1‐/β2‐adrenergic antagonist [3H]CGP‐12177 demonstrated that rat lymphocyte specific binding‐site density was highest, followed by steer and dairy cow lymphocytes, and lastly steer and dairy cow neutrophils. The β2‐adrenergic agonist terbutaline stimulated steer neutrophil adenosine 3,5‐cyclic monophosphate (cAMP) production, an effect increased by inclusion of ≥1 × 10?8 m phorbol 12‐myristate 13‐acetate (PMA), an activator of protein kinase C. Both terbutaline and the nonselective phosphodiesterase inhibitor 3‐isobutyl‐1‐methylxanthine (IBMX) independently decreased steer neutrophil superoxide anion production in a concentration‐dependent manner, with 1 × 10?4 m IBMX enhancing both the potency and efficacy of the terbutaline effect (up to 74% reduction in superoxide anion production). Superoxide anion production was also reduced by the synthetic cAMP analog 8‐bromo‐cAMP, which increased the potency of the IBMX effect on superoxide anion production. Taken together, these data demonstrate the presence of a β2‐adrenergic receptor signaling pathway in bovine neutrophils much like that described in other animal species, as well as the potential for an inflammatory stimulus to alter its function.  相似文献   

15.
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16.
ObjectiveTo determine the minimum infusion rate (MIR) of alfaxalone required to prevent purposeful movement of the extremities in response to noxious stimulation.Study DesignProspective, experimental.AnimalsEight healthy goats; four does and four wethers.MethodsAnaesthesia was induced with alfaxalone 3 mg kg−1 intravenously (IV). A continuous IV infusion of alfaxalone, initially at 0.2 mg kg−1 minute−1, was initiated. Following endotracheal intubation the goats breathed spontaneously via a circle breathing circuit delivering supplementary oxygen. The initial infusion rate was maintained for 30 minutes before testing for responses. The stimulus was clamping on the proximal (soft) part of one digit of the hoof with Vulsellum forceps for 60 seconds. In the absence or presence of purposeful movement of the extremities, the infusion rate was reduced or increased by 0.02 mg kg−1 minute−1 and held constant for 30 minutes before claw-clamping again. Alfaxalone MIR was calculated as the mean of the infusion rates that allowed and abolished movement. Cardio-respiratory parameters were measured. Recovery from general anaesthesia was timed and quality scored. Results are presented as median (range).ResultsThe MIR of alfaxalone was 0.16 (0.14–0.18) mg kg−1 minute−1 or 9.6 (8.4–10.8) mg kg−1 hour−1. Induction of and recovery from anaesthesia were excitement-free. Cardio-respiratory changes were minimal, although compared to baseline HR increased, and at 2 minutes post-induction, (prior to oxygen supplementation), PaO2 decreased significantly from 84 (80–88) to 70 (51–72) mmHg [11.2 (10.7–11.7) to 9.3 (6.8–9.6) kPa]. Sporadic muscle twitches, unrelated to depth of anaesthesia, were observed during the period of general anaesthesia. Time (minutes) to sternal recumbency and standing were 4.0 (3.0–10.0) and 41.5 (25.0–57.0) respectively.Conclusions and Clinical RelevanceAlfaxalone can be used for total intravenous anaesthesia (TIVA) in goats and is associated with minimal adverse effects. Oxygen supplementation is advised, especially when working at higher altitudes.  相似文献   

17.
ObjectivesAssess effects of benzodiazepine administration on the propofol dose required to induce anaesthesia in healthy cats, investigate differences between midazolam and diazepam, and determine an optimal benzodiazepine dose for co-induction.Study designProspective, randomised, blinded, placebo-controlled clinical trial.AnimalsNinety client-owned cats (ASA I and II) with a median (interquartile range) body mass of 4.0 (3.4–4.9) kg.MethodsAll cats received 0.01 mg kg−1 acepromazine and 0.2 mg kg−1 methadone intravenously (IV). Fifteen minutes later, sedation was scored on a scale of 1–5, with 5 indicating greatest sedation. Propofol, 2 mg kg−1, administered IV, was followed by either midazolam or diazepam at 0.2, 0.3, 0.4 or 0.5 mg kg−1 or saline 0.1 mL kg−1. Further propofol was administered until endotracheal intubation was possible. Patient signalment, sedation score, propofol dosage and adverse reactions were recorded.ResultsMidazolam and diazepam (all doses) significantly reduced the propofol dose required compared with saline (p < 0.001). There was no difference between midazolam and diazepam in propofol dose reduction (p = 0.488). All individual doses of midazolam reduced propofol requirement compared with saline (0.2 mg kg−1, p = 0.028; 0.3 mg kg−1, p = 0.006; 0.4 mg kg−1, p < 0.001; 0.5 mg kg−1, p = 0.009). Diazepam 0.2 mg kg−1 did not reduce the propofol dose compared with saline (p = 0.087), but the remaining doses did (0.3 mg kg−1, p = 0.001; 0.4 mg kg−1, p = 0.032; 0.5 mg kg−1, p = 0.041). Cats with sedation scores of 3 required less propofol than cats with scores of 2 (p = 0.008). There was no difference between groups in adverse events.Conclusions and clinical relevanceMidazolam (0.2–0.5 mg kg−1) and diazepam (0.3–0.5 mg kg−1) administered IV after 2 mg kg−1 propofol significantly reduced the propofol dose required for tracheal intubation.  相似文献   

18.
ObjectiveTo determine the potency ratio between S-ketamine and racemic ketamine as inductive agents for achieving tracheal intubation in dogs.Study designProspective, randomized, ‘blinded’, clinical trial conducted in two consecutive phases.Animals112 client-owned dogs (ASA I or II).MethodsAll animals were premedicated with intramuscular acepromazine (0.02 mg kg−1) and methadone (0.2 mg kg−1). In phase 1, midazolam (0.2 mg kg−1) with either 3 mg kg−1 of racemic ketamine (group K) or 1.5 mg kg−1 of S-ketamine (group S) was administered IV, for induction of anaesthesia and intubation. Up to two additional doses of racemic (1.5 mg kg−1) or S-ketamine (0.75 mg kg−1) were administered if required. In phase 2, midazolam (0.2 mg kg−1) with 1 mg kg−1 of either racemic ketamine (group K) or S-ketamine (group S) was injected and followed by a continuous infusion (1 mg kg minute−1) of each respective drug. Differences between groups were statistically analyzed via t-test, Fisher exact test and ANOVA for repeated measures.ResultsDemographics and quality and duration of premedication, induction and intubation were comparable among groups. During phase 1 it was possible to achieve tracheal intubation after a single dose in more dogs in group K (n = 25) than in group S (n = 16) (p = 0.046). A dose of 3 mg kg−1 S-ketamine allowed tracheal intubation in the same number of dogs as 4.5 mg kg−1 of racemic ketamine. The estimated potency ratio was 1.5:1. During phase 2, the total dose (mean ± SD) of S-ketamine (4.02 ±1.56 mg kg−1) and racemic ketamine (4.01 ± 1.42) required for tracheal intubation was similar.Conclusion and clinical relevanceRacemic and S-ketamine provide a similar quality of anaesthetic induction and intubation. S-ketamine is not twice as potent as racemic ketamine and, if infused, the potency ratio is 1:1.  相似文献   

19.
REASONS FOR STUDY: Xanthine oxidase (XO)-dependent production of superoxide anion and hydrogen peroxide, a characteristic of ischaemia-reperfusion injury, may contribute to the development of equine laminitis. OBJECTIVE: To determine the levels of XO and antioxidant enzymes (catalase, superoxide dismutase [SOD]) in the digital laminae of normal horses (CON) and horses in the developmental stage of laminitis using the black walnut extract (BWE) model. METHODS: Healthy horses (n = 12) were administered BWE (BWE group, n = 6), or water (CON group, n = 6) through a nasogastric tube. At the onset of leucopenia in the BWE-treated animals, all horses were anaesthetised, digital laminae and other samples collected rapidly and flash frozen, and the animals subjected to euthanasia. Extracts of the frozen tissues were assayed for the 2 conformational forms of xanthine: oxygen oxidoreductase (XOR), namely, xanthine dehydrogenase (XDH) and xanthine oxidase (XO), as well as the antioxidant enzymes, SOD and catalase. RESULTS: Extracts of liver, lungs and skin, but not digital laminae, from either CON or BWE-treated horses had endogenous SOD, whereas all had endogenous XO and catalase. The levels of XDH, XO and catalase were similar in extracts of laminae from CON and BWE-treated horses as was the ratio of XDH to XO in extracts. CONCLUSIONS AND POTENTIAL RELEVANCE: The absence of increased XO activity suggest against the involvement of this reactive oxygen intermediate-generating system in the development of laminar pathology in BWE-treated horses. Conversely, the absence of SOD from extracts of equine digital laminae, but not other tissues, suggests that the equine digital laminae are highly susceptible to damage by superoxide anion, produced, for example, by emigrant inflammatory leucocytes.  相似文献   

20.
Immunohistochemistry allows the localization of proteins to specific regions of the nephron. This article reports the identification and localization of proteins in situ within normal canine, feline, and mouse kidney by immunohistochemistry; maps their distribution; and compares results to previously reported findings in other species. The proteins investigated are aquaporin 1, aquaporin 2, calbindin D-28k, glutathione S-transferase-α, and Tamm-Horsfall protein. Aquaporins are integral membrane proteins involved in water transport across cell membranes. Calbindin D-28k is involved in renal calcium metabolism. Glutathione S-transferase-α is a protein that aids in detoxification and drug metabolism. The role of Tamm-Horsfall protein is not fully understood. Proposed functions include inhibition of calcium crystallization and reduction of bacterial urinary tract infection. The authors' findings in the dog are similar to those in other species: Specifically, the authors localize aquaporin 1 to the proximal convoluted tubule epithelium, vasa recta endothelium, and descending thin limbs; aquaporin 2 to collecting duct epithelium; and calbindin D-28k within distal convoluted tubule epithelium. Glutathione S-transferase-α has variable expression and is found in only the renal transitional epithelium in some individuals, in only the proximal straight tubules in others, or in both locations in others. Tamm-Horsfall protein localizes to thick ascending limb epithelium. These findings are similar in the cat, with the exception that aquaporin 1 is located in glomerular podocytes, in addition to proximal convoluted tubule epithelium, and glutathione S-transferase-α is found solely within the proximal convoluted tubule within all kidney samples examined. The mouse kidney is almost identical to the dog but expresses glutathione S-transferase-α in the glomeruli only.  相似文献   

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