Urea transport in isolated thick ascending limbs and collecting ducts from rats

1983 ◽  
Vol 245 (5) ◽  
pp. F634-F639 ◽  
Author(s):  
M. A. Knepper
Keyword(s):  
Thick Ascending Limb ◽  
Sprague Dawley ◽  
Urea Permeability ◽  
Sprague Dawley Rats ◽  
Collecting Ducts ◽  
Outer Stripe ◽  
Passive Absorption ◽  
Urinary Concentrating Ability

The use of pathogen-free rats allows the dissection and in vitro perfusion of several rat nephron segments not previously studied. In the present experiments, net urea fluxes were measured in isolated perfused cortical and medullary thick ascending limbs and cortical collecting ducts from pathogen-free Sprague-Dawley rats. No evidence for active transport of urea was found in either cortical or medullary thick ascending limbs. Permeabilities were calculated from urea fluxes measured with 5 mM urea either in the bath or perfusate and with no urea on the opposite side of the epithelium. Permeability coefficients (cm/s X 10(-5) +/- SE) in different portions of the thick ascending limb were: inner stripe, short-looped nephrons, 0.9 +/- 0.2; inner stripe, long-looped nephrons, 0.6 +/- 0.2 (not significantly different vs. short loops); outer stripe, 1.4 +/- 0.3 (P less than 0.05 vs. inner stripe); and cortical, 1.5 +/- 0.3 (P less than 0.05 vs. inner stripe). The relatively high urea permeability of thick ascending limbs in the outer stripe of the outer medulla and medullary rays is likely to permit substantial passive absorption of urea from these segments in vivo. This will contribute to dilution of the tubule fluid in thick ascending limbs and thus indirectly enhance urinary concentrating ability. In cortical collecting ducts, the urea permeability was relatively low both in the presence of 100 microU/ml arginine vasopressin in the bath (0.5 +/- 0.1 X 10(-5) cm/s) and in its absence (0.4 +/- 0.1). These permeability values are similar to values previously measured in rabbit cortical collecting ducts.

Independent desensitization of rat renal thick ascending limbs and collecting ducts to ADH

1989 ◽  
Vol 256 (4) ◽  
pp. F656-F663 ◽  
Author(s):  
I. Dublineau ◽  
J. M. Elalouf ◽  
P. Pradelles ◽  
C. de Rouffignac
Keyword(s):  
Collecting Duct ◽  
Synthetic Analogue ◽  
Thick Ascending Limb ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Collecting Ducts ◽  
Normal Rat ◽  
Series Of Experiments ◽  
High Doses

Recent micropuncture studies have demonstrated that administration of high doses of 1-deamino-8-D-arginine vasopressin (dDAVP), a synthetic analogue of vasopressin (AVP), causes desensitization of the thick ascending limb to AVP but may leave unaltered the effect of this hormone on the permeability to water of the collecting duct. In the present experiments, desensitization to AVP was studied by measuring adenosine 3',5'-cyclic monophosphate (cAMP) synthesis in microdissected cortical thick ascending limbs (CTAL) and cortical collecting ducts (CCD) incubated in vitro. Desensitization was induced by intramuscular injections of dDAVP (2 micrograms/day for 3 days). In a first series of experiments, performed on Brattleboro rats lacking circulating AVP, the effects of AVP on cAMP accumulation were reduced by 30% in CTAL of the rats given dDAVP, whereas in CCD no reduction was noted. Desensitization of CTAL was selective for AVP (i.e., homologous), the effects of glucagon being unaltered. In a second series of experiments, performed on Sprague-Dawley rats, a marked (up to 75% 2 h after dDAVP injection), homologous and reversible desensitization of CTAL to AVP was observed. However, here again no desensitization was obtained in CCD, indicating that in the normal rat, administration of 2 micrograms dDAVP also elicited preferential desensitization of CTAL.

scholarly journals Pharmacological comparison of four biopolymeric natural gums as hemostatic agents for management of bleeding wounds: preliminary in vitro and in vivo results

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Himanshu Kushwah ◽  
Nidhi Sandal ◽  
Meenakshi Chauhan ◽  
Gaurav Mittal
Keyword(s):  
Xanthan Gum ◽  
Guar Gum ◽  
Human Lymphocytes ◽  
Sprague Dawley ◽  
Gum Tragacanth ◽  
Civilian Trauma ◽  
Sprague Dawley Rats ◽  
Cytotoxicity Studies

Abstract Background Uncontrolled bleeding is one of the primary reasons for preventable death in both civilian trauma and military battle field. This study evaluates in vitro and in vivo hemostatic potential of four biopolymeric natural gums, namely, gum tragacanth, guar gum, xanthan gum, and gum acacia. In vitro evaluation of whole blood clotting time and erythrocyte agglutination assay were carried out. In vitro cytotoxicity studies with respect to each gum were done in human lymphocytes to ascertain percent cell viability. In vivo hemostatic potential of each gum (as sponge dressing and powder form) was evaluated in Sprague Dawley rats using tail bleeding assay and compared with commercially available hemostatic sponge. Other important parameters like (a) time taken for complete hemostasis, (b) amount of blood absorbed, (c) adherence strength of developed hemostatic dressing(s), (d) incidence of re-bleeding, and (e) survival of animals were also studied. Results Of the four test gums studied, xanthan gum (@3mg/ml of blood) and gum tragacanth (@35mg/ml of blood) were able to clot blood in least time (58.75±6.408 s and 59.00±2.082 s, respectively) and exhibited very good hemostatic potential in vitro. Except for xanthan gum, all other test gums did not exhibit any significant cytotoxicity at different time points till 24 h. In rat tail bleeding experiments, gum tragacanth sponge dressing and powder achieved hemostasis in least time (156.2±12.86 s and 76±12.55 s, respectively) and much earlier than commercially available product (333.3±38.84 s; p˂0.01). Conclusion Results indicate potential of gum tragacanth to be developed into a suitable hemostatic product.

Bioavailability in Vivo of Benzo[a]Pyrene Adsorbed to Diesel Particulate

1991 ◽  
Vol 7 (3) ◽  
pp. 125-139 ◽  
Author(s):  
David R. Bevan ◽  
David M. Ruggio
Keyword(s):  
Health Risks ◽  
Quantitative Description ◽  
Intratracheal Instillation ◽  
Direct Analysis ◽  
Sprague Dawley ◽  
Reasonable Estimate ◽  
Diesel Particulate ◽  
Sprague Dawley Rats

To evaluate health risks associated with exposure to particulates in the environment, it is necessary to quantify the bioavailability of carcinogens associated with the particulates. Direct analysis of bioavailability in vivo is most readily accomplished by adsorbing a radiolabeled form of the carcinogen to the particulate. A sam ple of native diesel particulate collected from an Oldsmobile die sel engine that contained 1.03 μ g benzo[ a] pyrene ( BaP)/ g particulate was supplemented with exogenous [ 3 H]- BaP to pro duce a particulate containing 2.62 μ g BaP/g. To insure that elu tion of BaP from native and [3 H] -BaP-supplemented particulate was similar, in vitro analyses were performed. When using phos pholipid vesicles composed of dimyristoylphosphatidylcholine (DMPC), 1.52% of total BaP was eluted from native particulate into the vesicles in 18 hrs; from [ 3 H] -BaP supplemented particu late, 1.68% was eluted. Using toluene as eluent, 2.55% was eluted from native particulate, and 8.25% from supplemented particulate, in 6 hrs. Supplemented particulate was then instilled intratracheally into male Sprague-Dawley rats and distribution of radioactivity was analyzed at selected times over 3 days. About 50% of radioactivity remained in lungs at 3 days following instil lation, with 30% being excreted into feces and the remainder dis tributed throughout the organs of the rats. To estimate the amount of radioactivity that entered feces through swallowing of a portion of the instilled dose, [3 H] -BaP-supplemented particu late was instilled intratracheally into rats that had a cannula sur gically implanted in the bile duct. Rate of elimination of radio activity into bile was monitored; 10.6% of radioactivity was re covered in 6 hr, an amount slightly lower than the 12.8% ex creted in 6 hrs into feces of animals with intact bile ducts. Our studies provide a quantitative description of the distribution of BaP and its metabolites following intratracheal instillation of diesel particulate. Because rates of elution of BaP in vitro are similar for native diesel particulate and particulate with supple mental [ 3H] -BaP, our results provide a reasonable estimate of the bioavailability in vivo of BaP associated with diesel particu late.

scholarly journals Regulation of mdrlb gene expression in Fischer, Wistar and Sprague-Dawley rats in vivo and in vitro

1996 ◽  
Vol 17 (3) ◽  
pp. 451-457 ◽  
Author(s):  
Barbara A. Hill ◽  
Paul C. Brown ◽  
Karl-Heinz Preisegger ◽  
Jeffrey A. Silverman
Keyword(s):  
Gene Expression ◽  
Sprague Dawley ◽  
Sprague Dawley Rats

scholarly journals Angiotensin II inhibits NaCl absorption in the rat medullary thick ascending limb

2004 ◽  
Vol 287 (3) ◽  
pp. F404-F410 ◽  
Author(s):  
Nicolas Lerolle ◽  
Soline Bourgeois ◽  
Françoise Leviel ◽  
Gaëtan Lebrun ◽  
Michel Paillard ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Plasma Membranes ◽  
Inhibitory Effect ◽  
Thick Ascending Limb ◽  
Sprague Dawley ◽  
Experimental Conditions ◽  
Nacl Absorption ◽  
Medullary Thick Ascending Limb

NaCl reabsorption in the medullary thick ascending limb of Henle (MTALH) contributes to NaCl balance and is also responsible for the creation of medullary interstitial hypertonicity. Despite the presence of angiotensin II subtype 1 (AT1) receptors in both the luminal and the basolateral plasma membranes of MTALH cells, no information is available on the effect of angiotensin II on NaCl reabsorption in MTALH and, furthermore, on angiotensin II-dependent medullary interstitial osmolality. MTALHs from male Sprague-Dawley rats were isolated and microperfused in vitro; transepithelial net chloride absorption ( JCl) as well as transepithelial voltage ( Vte) were measured. Luminal or peritubular 10−11 and 10−10 M angiotensin II had no effect on JCl or Vte. However, 10−8 M luminal or peritubular angiotensin II reversibly decreased both JCl and Vte. The effect of both luminal and peritubular angiotensin II was prevented by the presence of losartan (10−6 M). By contrast, PD-23319, an AT2-receptor antagonist, did not alter the inhibitory effect of 10−8 M angiotensin II. Finally, no additive effect of luminal and peritubular angiotensin II was observed. We conclude that both luminal and peritubular angiotensin II inhibit NaCl absorption in the MTALH via AT1 receptors. Because of intrarenal angiotensin II synthesis, angiotensin II concentration in medullary tubular and interstitial fluids may be similar in vivo to the concentration that displays an inhibitory effect on NaCl reabsorption under the present experimental conditions.

SYNTHESIS OF DNA AND LECITHIN IN TISSUE CULTURE AND OESTROGEN RECEPTOR ACTIVITY IN RAT MAMMARY TUMOURS DEPENDENT ON AND INDEPENDENT OF THE OVARY

1979 ◽  
Vol 81 (2) ◽  
pp. 183-198 ◽  
Author(s):  
ANNE-MARIE SCOTT ◽  
SUSAN MURPHY ◽  
R. A. HAWKINS
Keyword(s):  
Tissue Culture ◽  
Dna Synthesis ◽  
Oestrogen Receptor ◽  
Receptor Activity ◽  
Sprague Dawley ◽  
Mammary Tumours ◽  
Sprague Dawley Rats ◽  
The Media

Dimethylbenz(a)anthracene (DMBA)-induced and transplanted rat mammary tumours (2 lines) were examined for oestrogen receptor activity, and for sensitivity to hormones in vivo (by ovariectomy) and in vitro (by tissue culture). In vivo, the growth of all tumours induced by the administration of DMBA in random-bred Sprague–Dawley rats was found to be dependent on the ovary, whilst in all transplanted tumours (12 TG-3 and six TG-5 lines), maintained in an inbred strain of Sprague–Dawley rats, growth was found to be independent of the ovary. In vitro, the capacity for DNA synthesis in DMBA-induced tumours was better maintained after 24 h when insulin (10 μg/ml) and corticosterone (5 μg/ml) or insulin, corticosterone and prolactin (each 5 μg/ml) were present in the medium (five out of 12 and eight out of 11 tumours respectively); no effect of hormones in the media was detected after 48 h. In the transplanted tumours, no effect of hormones on DNA synthesis was detected after either 24 or 48 h of culture. Synthesis of lecithin was not detectably influenced by the presence of hormones in either DMBA-induced or transplanted tumours. Oestrogen receptor concentrations were, on average, significantly higher in the DMBA-induced tumours than in either line of transplanted tumour. For 22 DMBA-induced tumours and 15 transplanted tumours, the effect of hormones in vitro (`response') was directly correlated with receptor concentration at time 0 (Spearman's ρ = + 0·59) and inversely correlated with the rate of DNA synthesis (`basal') at time 0 (Spearman's ρ = −0·62). No single parameter or pair of parameters permitted accurate distinction between the tumour types.

scholarly journals Chronic Microcystin-LR Exposure Induces Hepatocarcinogenesis via Increased Gankyrin in Vitro and in Vivo

2018 ◽  
Vol 49 (4) ◽  
pp. 1420-1430 ◽  
Author(s):  
Lixiong He ◽  
Yujing Huang ◽  
Qiaonan Guo ◽  
Hui Zeng ◽  
Chuanfen Zheng ◽  
...  
Keyword(s):  
Low Dose ◽  
Soft Agar ◽  
Tumor Formation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
L02 Cells ◽  
Insight Into

Background/Aims: Our recent study indicated that the serum microcystin-LR (MC-LR) level is positively linked to the risk of human hepatocellular carcinoma (HCC). Gankyrin is over-expressed in cancers and mediates oncogenesis; however, whether MC-LR induces tumor formation and the role of gankyrin in this process is unclear. Methods: We induced malignant transformation of L02 liver cells via 35 passages with exposure to 1, 10, or 100 nM MC-LR. Wound healing, plate and soft agar colony counts, and nude mice tumor formation were used to evaluate the tumorigenic phenotype of MC-LR-treated cells. Silencing gankyrin was used to confirm its function. We established a 35-week MC-LR exposure rat model by twice weekly intraperitoneal injection with 10 μg/kg body weight. In addition, 96 HCC patients were tested for tumor tissue gankyrin expression and serum MC-LR levels. Results: Chronic low-dose MC-LR exposure increased proliferation, mobility, clone and tumor formation abilities of L02 cells as a result of gankyrin activation, while silencing gankyrin inhibited the carcinogenic phenotype of MC-LR-treated cells. MC-LR also induced neoplastic liver lesions in Sprague-Dawley rats due to up-regulated gankyrin. Furthermore, a trend of increased gankyrin was observed in humans exposed to MC-LR. Conclusion: These results suggest that MC-LR induces hepatocarcinogenesis in vitro and in vivo by increasing gankyrin levels, providing new insight into MC-LR carcinogenicity studies.

Comparative studies on tryptophan binding to hepatic nuclear envelopes in Sprague-Dawley and Lewis rats

1994 ◽  
Vol 267 (2) ◽  
pp. R502-R507 ◽  
Author(s):  
H. Sidransky ◽  
E. Verney
Keyword(s):  
Inflammatory Diseases ◽  
Specific Binding ◽  
Quantitative Difference ◽  
Sprague Dawley ◽  
Lewis Rats ◽  
Sprague Dawley Rats ◽  
Nuclear Rna ◽  
Eosinophilia Myalgia Syndrome

Since Lewis rats are susceptible to many inflammatory diseases and have been used in an experimental model of the eosinophilia-myalgia syndrome, we investigated whether Lewis rats would respond to L-tryptophan as have Sprague-Dawley rats reported earlier. In this comparative study using females of both strains, we observed a decrease in the affinity of in vitro L-tryptophan binding to hepatic nuclei and nuclear envelopes of Lewis rats compared with Sprague-Dawley rats. However, in vivo stimulatory effects of administering L-tryptophan on hepatic polyribosomal aggregation, protein synthesis, and nuclear RNA release were similar in both strains. In vitro [3H]tryptophan binding to hepatic nuclear envelopes, using L-tryptophan implicated in cases of the eosinophilia-myalgia syndrome, revealed less specific binding than when using nonimplicated L-tryptophan in both strains. The possible significance of the quantitative difference in the binding affinity of L-tryptophan to hepatic nuclei of Lewis rats compared with those of Sprague-Dawley rats is as yet undetermined.

NHE3 phosphorylation at serines 552 and 605 does not directly affect NHE3 activity

2007 ◽  
Vol 293 (1) ◽  
pp. F212-F218 ◽  
Author(s):  
Hetal S. Kocinsky ◽  
Diane W. Dynia ◽  
Tong Wang ◽  
Peter S. Aronson
Keyword(s):  
Cell Model ◽  
Membrane Vesicles ◽  
Sprague Dawley ◽  
Opossum Kidney ◽  
Sprague Dawley Rats ◽  
Sodium Hydrogen Exchanger ◽  
Tightly Coupled ◽  
Type 3

Direct phosphorylation of sodium hydrogen exchanger type 3 (NHE3) is a well-established physiological phenomenon; however, the exact role of NHE3 phosphorylation in its regulation remains unclear. The objective of this study was to evaluate whether NHE3 phosphorylation at serines 552 and 605 is physiologically regulated in vivo and, if so, whether changes in phosphorylation at these sites are tightly coupled to changes in transport activity. To this end, we directly compared PKA-induced NHE3 inhibition with site-specific changes in NHE3 phosphorylation in vivo and in vitro. In vivo, PKA was activated using an intravenous infusion of parathyroid hormone in Sprague-Dawley rats. In vitro, PKA was activated directly in opossum kidney (OKP) cells using forskolin and IBMX. NHE3 activity was assayed in microvillar membrane vesicles in the rat model and by 22Na uptake in the OKP cell model. In both cases, NHE3 phosphorylation at serines 552 and 605 was determined using previously characterized monoclonal phosphospecific antibodies directed to these sites. In vivo, we found dramatic changes in NHE3 phosphorylation at serines 552 and 605 with PKA activation but no corresponding alteration in NHE3 activity. This dissociation between NHE3 phosphorylation and activity was further verified in OKP cells in which phosphorylation clearly preceded transport inhibition. We conclude that although phosphorylation of NHE3 at serines 552 and 605 is regulated by PKA both in vivo and in vitro, phosphorylation of these sites does not directly alter Na+/H+ exchange activity.

scholarly journals Development of Risperidone PLGA Microspheres

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Susan D’Souza ◽  
Jabar A. Faraj ◽  
Stefano Giovagnoli ◽  
Patrick P. DeLuca
Keyword(s):  
Steady State ◽  
Sustained Release ◽  
Sustained Delivery ◽  
Plga Microspheres ◽  
Sprague Dawley ◽  
Multiple Dosing ◽  
Duration Of Action ◽  
Sprague Dawley Rats

The aim of this study was to design and evaluate biodegradable PLGA microspheres for sustained delivery of Risperidone, with an eventual goal of avoiding combination therapy for the treatment of schizophrenia. Two PLGA copolymers (50 : 50 and 75 : 25) were used to prepare four microsphere formulations of Risperidone. The microspheres were characterized by several in vitro techniques. In vivo studies in male Sprague-Dawley rats at 20 and 40 mg/kg doses revealed that all formulations exhibited an initial burst followed by sustained release of the active moiety. Additionally, formulations prepared with 50 : 50 PLGA had a shorter duration of action and lower cumulative AUC levels than the 75 : 25 PLGA microspheres. A simulation of multiple dosing at weekly or 15-day regimen revealed pulsatile behavior for all formulations with steady state being achieved by the second dose. Overall, the clinical use of Formulations A, B, C, or D will eliminate the need for combination oral therapy and reduce time to achieve steady state, with a smaller washout period upon cessation of therapy. Results of this study prove the suitability of using PLGA copolymers of varying composition and molecular weight to develop sustained release formulations that can tailor in vivo behavior and enhance pharmacological effectiveness of the drug.

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