scholarly journals Mechanism of dopamine inhibition of renal phosphate transport.

1992 ◽  
Vol 2 (11) ◽  
pp. 1601-1607
Author(s):  
J Isaac ◽  
R P Glahn ◽  
M M Appel ◽  
M Onsgard ◽  
T P Dousa ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Brush Border Membrane ◽  
Phosphate Transport ◽  
Constant Infusion ◽  
Saline Control ◽  
Control Group ◽  
Sprague Dawley ◽  
Pi Transport ◽  
Sprague Dawley Rats ◽  
Dependent Transport

Dopamine (DA) is natriuretic and phosphaturic. However, whether the effect of DA on Pi reabsorption is a consequence of its effect on sodium transport is not known. Therefore, this study was performed to determine the effect of DA on the maximal transport of phosphate (TmPi), and upon the capacity of renal proximal brush border membrane (BBM) for (Naextra-vesicular greater than Naintravesicular)-gradient-dependent transport of Pi, as compared with the transport of other solutes. Graded infusions of Pi (0, 1, 2, and 3 mumols/min) were given to thyroparathyroidectomized male Sprague-Dawley rats in the presence of vehicle (0.9% NaCl; N = 5), DA 15 micrograms/kg/min; N = 6), or parathyroid hormone ((PTH); 1 U/kg/min; N = 5). The TmPi for rats infused with DA (3.3 +/- 0.3 mumol/mL) was significantly less than the TmPi for saline control rats (4.4 +/- 0.2 mumol/mL). Rats infused with PTH exhibited the lowest TmPi (1.8 +/- 0.3 mumol/mL). No differences in sodium excretion were observed among any of the groups. Na-dependent Pi transport was studied in BBM vesicles (BBMV) prepared from rats fed a low-phosphate diet for 2 days that were anesthetized, acutely thyroparathyroidectomized, and systemically infused with DA (350 micrograms bolus, plus 35 micrograms/kg/min; N = 8), PTH (33 U/kg bolus, followed by a continuous infusion of 1 U/kg/min; N = 6), or vehicle (1 mL/kg bolus, plus 2 mL/h constant infusion of 0.9% NaCl; N = 8) for 90 min. DA significantly inhibited the Na cotransport of Pi by 22.4 +/- 4.1% (P less than 0.01) as compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of TRH on thyrotroph function and number in rat pituitaries transplanted to renal capsule

1986 ◽  
Vol 251 (5) ◽  
pp. E563-E568
Author(s):  
S. Amr ◽  
S. S. Lippman ◽  
B. D. Weintraub
Keyword(s):  
Biologically Active ◽  
Constant Infusion ◽  
Control Group ◽  
Mrna Levels ◽  
Renal Capsule ◽  
Sprague Dawley ◽  
Subunit Mrna ◽  
Sprague Dawley Rats ◽  
Hypophysectomized Rats ◽  
Hypothalamic Influence

We investigated the function of thyrotrophs in rat pituitaries that were transplanted under the renal capsule of 3-wk-old male Sprague-Dawley rats, which were either intact or hypophysectomized. Groups of 12 animals were implanted with osmotic minipumps that delivered a constant infusion of either thyrotropin-releasing hormone (TRH; 1 mg X kg-1 X day-1) or normal saline for 1 wk. In hypophysectomized rats, TRH infusion led to the appearance of substantial amounts of biologically active serum TSH and prevented the hypothyroidism that occurred in the control group. However, TRH did not change the transplant contents of DNA, immunoactive TSH, and mRNA levels for TSH subunits. Comparison of sellar and renal pituitary tissues, obtained from intact rats after 1 wk of either saline or TRH infusion, showed that removal of the pituitary from hypothalamic influence resulted in a 90% depletion of the thyrotroph TSH content. TRH infusion depleted only 63% of the TSH content of sellar thyrotrophs. The mRNA levels for TSH beta-subunit were similar in sellar and transplanted pituitaries and did not significantly change after TRH infusion. When immunocytochemically stained using rat TSH antiserum, the thyrotrophs in pituitary transplants were morphologically and numerically indistinguishable from the thyrotrophs in sellar pituitaries, in the presence or absence of TRH. These data indicate that in transplanted pituitary, for up to 1 wk of a constant infusion, TRH does not significantly affect either the number of thyrotrophs or their ability to synthesize TSH subunit mRNA. However, it is required to maintain released TSH in circulation, since TSH levels were low in the absence of TRH.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Histological and biochemical effects of Cinnamomum cassia nanoparticles in kidneys of diabetic Sprague-Dawley rats

2019 ◽  
Author(s):  
Koffi Kouame ◽  
Aniekan Imo Peter ◽  
Edidiong Nnamso Akang ◽  
Roshila Moodley ◽  
Edwin Coleridge Naidu ◽  
...  
Keyword(s):  
Body Weight ◽  
Fasting Blood Glucose ◽  
Kidney Tissue ◽  
Saline Control ◽  
Control Group ◽  
Sprague Dawley ◽  
Cinnamomum Cassia ◽  
Sprague Dawley Rats ◽  
Group A ◽  
Group B

This study investigated the antidiabetic activity of Cinnamomum cassia (C. cassia, Cc) silver nanoparticles (CcAgNPS) and effects of C. cassia on the kidneys of rats with induced type 2 diabetes. Twenty-four Sprague-Dawley rats weighing 250 ± 20 g were induced with diabetes by intraperitoneal injection of streptozotocin (STZ, 60 mg/kg). Animals were randomly assigned to one of four groups (n = 6) and treated for eight weeks with normal saline (control, group A), 5 mg/kg of CcAgNPs (group B), 10 mg/kg of CcAgNPs (group C), or 200 mg/kg of Cc (group D). Body weight and fasting blood glucose (FBG) was measured weekly and fortnightly, respectively. At the end of experiments, animals were euthanized, blood and kidney tissue samples were collected for biochemistry (oxidative stress markers and renal function parameters) and kidneys were harvested for histology (PAS and HE staining). Body weight was significantly higher in group B and C vs. control (p < 0.05), while no significant differences were observed in the kidney-to-body weight ratio between groups. FBG, glutathione, malondialdehyde, alanine aminotransferase, aspartate aminotransferase, serum urea and creatinine were significantly lower in group B, C and/or D vs. control (all p < 0.05). In group A, severe distortion of the glomerular network was observed, marked by the loss of capsular integrity, thickened basement membrane, tubular cells with pyknotic nuclei, vacuolization, and interstitial space with infiltrations. These adverse effects were mitigated by 5 mg/kg and 10 mg/kg of CcAgNPs. Our study confirms structural and functional damage to kidneys caused by diabetes. CcAgNPs have a regenerative potential in diabetes-induced kidney damage and may be used as an antidiabetic agent.

Phosphaturic effect of L-NMMA in the presence of parathyroid hormone

1996 ◽  
Vol 271 (6) ◽  
pp. R1477-R1480
Author(s):  
M. J. Onsgard-Meyer ◽  
R. J. Kerrigan ◽  
M. Collins ◽  
A. A. Khraibi ◽  
F. G. Knox
Keyword(s):  
Parathyroid Hormone ◽  
Fractional Excretion ◽  
Parathyroid Glands ◽  
Constant Infusion ◽  
Sprague Dawley ◽  
Phosphate Excretion ◽  
Sprague Dawley Rats ◽  
Additional Group ◽  
Renal Clearances ◽  
Intact Rats

The objective of this study was to examine the effect of NG-monomethyl-L-arginine (L-NMMA) on phosphate excretion in the presence and absence of parathyroid hormone (PTH). Renal clearances were obtained before and during infusion of L-NMMA (15 mg/kg bolus and 500 micrograms.kg-1.min-1 infusion) in Sprague-Dawley rats with intact parathyroid glands (n = 6), in thyroparathyroidectomized (TPTX) rats receiving a constant infusion of PTH-(1-34) (0.01-0.03 U.kg-1.min-1) (n = 11) throughout the experiment, or in TPTX rats, that received an acute infusion of PTH-(1-34) (33 U/kg bolus and 1 U.kg-1.min-1 infusion) after L-NMMA infusion alone (n = 7). In rats with intact parathyroid glands, L-NMMA increased the fractional excretions of phosphate (FEPi) and sodium (FENa) and mean arterial pressure (MAP) (delta 8.6 +/- 1.5%, delta 0.62 +/- 0.1%, and delta 26.7 +/- 4.9 mmHg, respectively; P < 0.05). In TPTX rats receiving a constant infusion of PTH, L-NMMA again increased FEPi, FENa, and MAP (delta 9.5 +/- 3.6%, delta 1.1 +/- 0.4%, and delta 28.4 +/- 4.5 mmHg, respectively; P < 0.05). However, in TPTX rats, L-NMMA alone did not increase FEPi (delta 0.9 +/- 0.3%), whereas the subsequent infusion of PTH with L-NMMA increased FEPi (delta 15.6 +/- 3.1%; P < 0.05). In an additional group of intact and TPTX rats, the fractional excretion of lithium (FELi) was measured as an index of proximal reabsorption. L-NMMA increased FELi in intact rats (delta 13.2 +/- 2.6%; P < 0.05), but not in TPTX rats (delta 4.2 +/- 3.3%). In conclusion, L-NMMA increases phosphate excretion in association with increases in MAP and FENa, and this phosphaturic effect is dependent on the presence of PTH.

Effect of Maternally Administered Methadone on Discrimination Learning of Rat Offspring

1980 ◽  
Vol 50 (3_suppl) ◽  
pp. 1119-1124 ◽  
Author(s):  
Steven Van Wagoner ◽  
Judith Risser ◽  
Marcia Moyer ◽  
David Lasky
Keyword(s):  
Discrimination Learning ◽  
Saline Control ◽  
Control Group ◽  
Shape Discrimination ◽  
Sprague Dawley ◽  
Saline Control Group ◽  
Rat Offspring ◽  
Sprague Dawley Rats ◽  
Methadone Group

Shape discrimination learning by four groups of 150-day-old Sprague-Dawley rats was studied. The groups were the offspring of mothers on the following schedules: (1) prenatal and postnatal methadone, (2) prenatal methadone and postnatal saline, (3) prenatal and postnatal methadone, and (4) prenatal and postnatal saline. The hypothesis investigated was that the methadone groups would show a deficit in learning when compared to the saline-control group. This hypothesis was upheld for the prenatal methadone group and the postnatal methadone group.

Effect of potassium dichromate on renal brush border membrane enzymes and phosphate transport in rats

2005 ◽  
Vol 24 (12) ◽  
pp. 631-638 ◽  
Author(s):  
S Fatima ◽  
N A Arivarasu ◽  
A A Banday ◽  
A N K Yusufi ◽  
R Mahmood
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Potassium Dichromate ◽  
Rat Kidney ◽  
Maximum Velocity ◽  
Complete Recovery ◽  
Phosphate Transport ◽  
Saline Control ◽  
Pi Transport ◽  
Renal Brush Border Membrane

Chromium is widely used in industry but exposure to chromium compounds in the workplace can result in nephrotoxicity. Various nephrotoxicants affect the brush border membrane (BBM) lining the epithelial cells of the proximal tubule, but there have been no studies regarding the effect of potassium dichromate (K2Cr2O7), a hexava-lent chromium compound, on renal BBM. In the present work, the effect of administering a single intraperitoneal dose (15 mg/kg body weight) of K2Cr2O7 on rat renal BBM enzymes and inorganic phosphate (Pi) transport was studied. The animals were administered normal saline (control) or K2Cr2O7 and sacrificed 1, 2, 4 and 8 days after treatment. K2Cr2O7 induced reversible damage to the rat kidney function as indicated by serum creatinine (Scr) and urea nitrogen levels. The activities of BBM marker enzymes were significantly decreased in isolated BBM vesicles (BBMV) and homogenates of cortex and medulla on 1, 2 and 4 days after administration of K2Cr2O7with complete recovery to control values after 8 days. The decrease in the activities of the enzymes was mainly due to changes in maximum velocity (Vmax) values, while the Michaelis constant (Km) remained unchanged. The sodium dependent Pi transport across BBMV was reduced by 50% after treatment with K2Cr2O7. Thus, the administration of a single dose of K2Cr2O7 leads to impairment in the functions of renal BBM. These results suggest that the nephrotoxicity of K2Cr2O7 may be mediated, at least in part, by its effect on renal BBM.

scholarly journals Skeletal Muscle Metabolomic Responses to Endurance and Resistance Training in Rats under Chronic Unpredictable Mild Stress

2021 ◽  
Vol 18 (4) ◽  
pp. 1645
Author(s):  
Xiangyu Liu ◽  
Xiong Xue ◽  
Junsheng Tian ◽  
Xuemei Qin ◽  
Shi Zhou ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Endurance Exercise ◽  
Field Tests ◽  
Treadmill Running ◽  
Control Group ◽  
Mild Stress ◽  
Chronic Unpredictable Mild Stress ◽  
Sprague Dawley ◽  
Exercise Interventions ◽  
Sprague Dawley Rats

The objectives of this study were to compare the antidepressant effects between endurance and resistance exercise for optimizing interventions and examine the metabolomic changes in different types of skeletal muscles in response to the exercise, using a rat model of chronic unpredictable mild stress (CUMS)-induced depression. There were 32 male Sprague-Dawley rats randomly divided into a control group (C) and 3 experimental groups: CUMS control (D), endurance exercise (E), and resistance exercise (R). Group E underwent 30 min treadmill running, and group R performed 8 rounds of ladder climbing, 5 sessions per week for 4 weeks. Body weight, sucrose preference, and open field tests were performed pre and post the intervention period for changes in depressant symptoms, and the gastrocnemius and soleus muscles were sampled after the intervention for metabolomic analysis using the 1H-NMR technique. The results showed that both types of exercise effectively improved the depression-like symptoms, and the endurance exercise appeared to have a better effect. The levels of 10 metabolites from the gastrocnemius and 13 metabolites from the soleus of group D were found to be significantly different from that of group C, and both types of exercise had a callback effect on these metabolites, indicating that a number of metabolic pathways were involved in the depression and responded to the exercise interventions.

Parathyroid Hormone- and Deoxycorticosterone Acetate-Induced Hypertension in the Rat

1980 ◽  
Vol 58 (5) ◽  
pp. 365-371 ◽  
Author(s):  
A. Berthelot ◽  
A. Gairard
Keyword(s):  
Parathyroid Hormone ◽  
Hormone Secretion ◽  
Sprague Dawley ◽  
Physiological Concentration ◽  
Deoxycorticosterone Acetate ◽  
Calcium Diet ◽  
Arterial Blood ◽  
Sprague Dawley Rats ◽  
High Calcium ◽  
High Calcium Diet

1. Hypertension induced by treatment with deoxycorticosterone acetate and sodium chloride was studied in male Sprague-Dawley rats and related to parathyroid hormone secretion. 2. Lack of parathyroid hormone (due to parathyroidectomy) or decreased parathormone secretion (due to a high-calcium diet) partially inhibited the development of arterial hypertension. 3. In contrast, in thyroparathyroidectomized rats supplemented with thyroxine, the administration of parathyroid hormone rapidly elevated arterial blood pressure. 4. Maintaining a physiological concentration of serum calcium in the absence of parathyroid hormone (by feeding a high-calcium diet to parathyroidectomized rats) was not sufficient to establish mineralocorticoid hypertension. 5. These results show that parathyroid hormone is necessary for the complete development of mineralocorticoid hypertension.

Rapid determination of glomerular filtration rate by single-bolus inulin: a comparison of estimation analyses

1998 ◽  
Vol 84 (6) ◽  
pp. 2154-2162 ◽  
Author(s):  
Cord Sturgeon ◽  
Albert D. Sam ◽  
William R. Law
Keyword(s):  
Mathematical Model ◽  
Glomerular Filtration Rate ◽  
Mathematical Models ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Rapid Determination ◽  
Constant Infusion ◽  
Sprague Dawley ◽  
Single Bolus ◽  
Sprague Dawley Rats

Rapid measurement of glomerular filtration rate (GFR) by an inulin single-bolus technique would be useful, but its accuracy has been questioned. We hypothesized that reported inaccuracies reflect the use of inappropriate mathematical models. GFR was measured in 14 intact and 5 unilaterally nephrectomized conscious male Sprague-Dawley rats (mean weight 368 ± 12 g) by both single-bolus (25 mg/kg) and constant-infusion techniques (0.693 mg ⋅ kg−1 ⋅ min−1). The temporal decline in plasma inulin concentration was analyzed through biexponential curve fitting, which accounted for renal inulin loss before complete vascular and interstitial mixing. We compared our mathematical model based on empirical rationale with those of other investigators whose studies suggest inaccuracy of single-bolus methods. Our mathematical model yielded GFR values by single bolus that agreed with those obtained by constant infusion [slope = 0.94 ± 0.16 (SE); y intercept = 0.23 ± 0.64; r = 0.82]. In comparison to the data obtained by constant inulin infusion, this method yielded a very small bias of −0.0041 ± 0.19 ml/min. Two previously reported models yielded unsatisfactory values (slope = 1.46 ± 0.34, y intercept = 0.47 ± 1.5, r = 0.72; and slope = 0.17 ± 1.26, y intercept = 17.15 ± 5.14, r = 0.03). The biases obtained by using these methods were −2.21 ± 0.42 and −13.90 ± 1.44 ml/min, respectively. The data indicate that when appropriate mathematical models are used, inulin clearance after single-bolus delivery can be used to measure GFR equivalent to that obtained by constant infusion of inulin. Attempts to use methods of analysis for simplicity or expediency can result in unacceptable measurements relative to the clinical range of values seen.

Ranitidine as an alcohol dehydrogenase inhibitor in acute methanol toxicity in rats

2009 ◽  
Vol 29 (2) ◽  
pp. 93-101 ◽  
Author(s):  
Amal A El-Bakary ◽  
Sahar A El-Dakrory ◽  
Sohayla M Attalla ◽  
Nawal A Hasanein ◽  
Hala A Malek
Keyword(s):  
Alcohol Dehydrogenase ◽  
High Performance ◽  
Negative Control Group ◽  
Positive Control ◽  
Negative Control ◽  
Control Group ◽  
Sprague Dawley ◽  
Blood Samples ◽  
Methanol Poisoning ◽  
Sprague Dawley Rats

Methanol poisoning is a hazardous intoxication characterized by visual impairment and formic acidemia. The therapy for methanol poisoning is alcohol dehydrogenase (ADH) inhibitors to prevent formate accumulation. Ranitidine has been considered to be an inhibitor of both gastric alcohol and hepatic aldehyde dehydrogenase enzymes. This study aimed at testing ranitidine as an antidote for methanol acute toxicity and comparing it with ethanol and 4-methyl pyrazole (4-MP). This study was conducted on 48 Sprague-Dawley rats, divided into 6 groups, with 8 rats in each group (one negative control group [C1], two positive control groups [C2, C3] and three test groups [1, 2 and 3]). C2, C3 and all test groups were exposed to nitrous oxide by inhalation, then, C3 group was given methanol (3 g/kg orally). The three test groups 1, 2 and 3 were given ethanol (0.5 g/kg orally), 4-MP (15 mg/kg intraperitoneally) and ranitidine (30 mg/kg intraperitoneally), respectively, 4 hours after giving methanol. Rats were sacrificed and heparinized, cardiac blood samples were collected for blood pH and bicarbonate. Non-heparinized blood samples were collected for formate levels by high performance liquid chromatography. Eye balls were enucleated for histological examination of the retina. Ranitidine corrected metabolic acidosis (p = .025), decreased formate levels (p = .014) and improved the histological findings in the retina induced by acute methanol toxicity.

Mineralocorticoid Receptor Activation by Aldosterone or Corticosterone Induces Hypertension, Myocardial Infarction and Proteinuria

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 723-723
Author(s):  
Qing-Feng Tao ◽  
Diego Martinez vasquez ◽  
Ricardo Rocha ◽  
Gordon H Williams ◽  
Gail K Adler
Keyword(s):  
Myocardial Infarction ◽  
Drinking Water ◽  
Mineralocorticoid Receptor ◽  
Critical Role ◽  
Weight Ratio ◽  
Myocardial Necrosis ◽  
Receptor Activation ◽  
Control Group ◽  
Sprague Dawley ◽  
Sprague Dawley Rats

P165 Aldosterone through its interaction with the mineralocorticoid receptor (MR) plays a critical role in the development of hypertension and cardiovascular injury (CVI). Normally, MR is protected by 11β-hydroxysteroid dehydrogenase (11β-HSD) which inactivates glucocorticoids preventing their binding to MR. We hypothesis that if activation of MR by either aldosterone or glucocorticoids induces hypertension and CVI, then the inhibition of 11β-HSD with glycyrrhizin (GA), a natural inhibitor of 11β-HSD, should induce damage similar to that observed with aldosterone. Sprague-Dawley rats were uninephrectomized, and treated for 4 weeks with 1% NaCl (in drinking water) for the control group, 1% NaCl + aldosterone infusion (0.75 μg/h), or 1% NaCl + GA (3.5 g/l in drinking water). After 4 weeks, aldosterone and GA caused significant increases in blood pressure compared to control rats ([mean ± SEM] 211± 9, 205 ± 12, 120 ± 9 mmHg, respectively, p<0.001). Both aldosterone- and GA-treated rats had a significant increase in proteinuria (152.2 ± 8.7 and 107.7 ± 19.5 mg/d, respectively) versus controls (51.2 ± 9.5 mg/d). There was a significant increase (p<0.001) in heart to body weight ratio in the rats treated with aldosterone or GA compared with control (3.92 ± 0.10, 3.98 ± 0.88, and 3.24 ± 0.92 mg/g, respectively). Hearts of GA and aldosterone treated rats showed similar histological changes consisting of biventricular myocardial necrosis and fibrinoid necrosis of small coronary arteries and arterioles. These data suggests that in rodents activation of MR by either aldosterone or corticosterone leads to severe hypertension, vascular injury, proteinuria and myocardial infarction. Thus, 11β-HSD plays an important role in protecting the organism from injury.

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