Chronic CEI alters effect of low Na+ diet in normal and coarcted pups. I. BP, renin, and GFR

1989 ◽  
Vol 256 (2) ◽  
pp. R523-R530
Author(s):  
S. P. Bagby ◽  
E. Fuchs
Keyword(s):  
Enzyme Inhibitor ◽  
Phase 1 ◽  
Extracellular Volume ◽  
Normal Diet ◽  
High Dose ◽  
Ang Ii ◽  
Functional Responses ◽  
Renin Substrate ◽  
Low Sodium ◽  
And Control

To assess the renin-angiotensin (RA) dependence of evolving neonatally induced coarctation hypertension (NICH) in inbred pups, we randomized sex-matched littermates to a high dose of converting-enzyme inhibitor (CEI:MK-421) or placebo from the time of neonatal aortic banding (coarcted) vs. no banding (control). In phase 1 studies, pups were examined serially on normal diet (Bagby and Fuchs, Hypertension In press.): chronic CEI lowered systolic blood pressure (BP) equally in coarcted and controls and failed to prevent systolic BP excess in coarcted dogs. In phase 2 studies, the same pups were exposed to a low sodium (LS) diet at 4 mo of age, a time when the untreated NICH model exhibits increased forelimb systolic BP. Measurements of systolic BP, RA components, renal function, and extracellular volume (ECV) were made before and serially during 12 days on the LS diet. Responses of coarcted and control pups to the LS diet were similar, with or without CEI, providing no evidence for exaggerated angiotensin II (ANG II) dependence in evolving NICH. Independently of coarctation status, chronic CEI significantly modified RA and renal functional responses to the LS diet: a greater renin rise but abnormal renin substrate fall, thus no rise in ANG I or ANG I generation rate; a greater rise in creatinine and a trend toward a greater fall in glomerular filtration rate (GFR). Despite these findings compatible with sustained ANG II deficit, chronic CEI unexpectedly failed to impair maintenance of systolic BP during a superimposed LS diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic CEI alters effect of low Na+ diet in normal and coarcted pups. II. Na+ and H2O balance

1989 ◽  
Vol 256 (2) ◽  
pp. R531-R540
Author(s):  
S. P. Bagby ◽  
E. Fuchs
Keyword(s):  
Water Conservation ◽  
Enzyme Inhibitor ◽  
Present Report ◽  
Phase 1 ◽  
Free Water ◽  
High Dose ◽  
Ang Ii ◽  
Functional Responses ◽  
Water Diuresis ◽  
Renal Handling

To assess angiotensin (ANG II) dependence of evolving neonatally induced coarctation hypertension (NICH) in inbred pups, we randomized sex-matched littermates to high-dose converting enzyme inhibitor (CEI: MK-421, 3 mg/kg) or placebo from the time of neonatal aortic banding (coarcted) vs. no banding (control). During phase 1 studies over 4 mo postbanding during ad libitum Na+ intake (Bagby and Fuchs, Hypertension Dallas in press). CEI failed to prevent evolution of proximal blood pressure (BP) excess or to impair renal function. Phase 2 studies examine, in the same pups, responses to low Na+ (LS) diet superimposed on chronic CEI at 4 mo, timed to allow development of BP increase in untreated NICH. The present report details metabolic handling and balances of Na+, K+, and fluid for 3 days before (normal Na+ intake) and daily for 11 days after initiation of LS diet, a companion paper describes BP, renin-angiotensin (RA), and renal functional responses. In no case did metabolic responses of coarcted pups to LS diet differ from those of controls, whether on CEI or placebo, whereas responses to LS diet and to CEI reveal positive findings of independent interest. LS diet induced expected renal and fecal Na+ conservation, no net effect on K+ balance, and, despite unexpected free-water diuresis, mild hyponatremia. Chronic CEI impaired maximal renal (but not fecal) Na+ conservation during LS diet, caused exaggerated free-water diuresis but no change in fluid balance, and thus, with the larger Na+ deficit, accounted for greater hyponatremia. CEI caused no net effect on K+ balance. Results indicate normal renal handling of fluid, Na+, and K+ in evolving NICH and provide no evidence for selective intrarenal RA activation or exaggerated ANG II dependence. Findings also suggest that, during LS diet, ANG II is 1) essential for maximum renal Na+ conservation and normal free-water handling, and 2) not essential for fecal Na+ and water conservation or for maintenance of normal water and K+ balances. Results are also compatible with a CEI-induced thirst stimulation and/or osmotic insensitivity and with functional vasopressin deficiency during LS diet.

scholarly journals Ammonia production and secretion by S3 proximal tubule segments from acidotic mice: role of ANG II

2004 ◽  
Vol 287 (4) ◽  
pp. F707-F712 ◽  
Author(s):  
Glenn T. Nagami
Keyword(s):  
Proximal Tubule ◽  
Ang Ii ◽  
Ammonia Production ◽  
Low Sodium ◽  
Luminal Perfusion ◽  
And Control ◽  
Acid Loading ◽  
Proximal Tubule Segments ◽  
Secretion Rates

ANG II has potent effects on ammonia production and secretion rates by the proximal tubule and is found in substantial concentrations in the lumen of the proximal tubule in vivo. Because our previous studies demonstrated that acid loading enhanced the stimulatory effects of ANG II on ammonia production and secretion by S2 proximal tubule segments, we examined the effect of ANG II on ammonia production and secretion by isolated, perfused S3 segments from nonacidotic control mice and acidotic mice given NH4Cl for 7 days. In the absence of ANG II, ammonia production and secretion rates were no different in S3 segments from acidotic and control mice. By contrast, when ANG II was present in the luminal perfusion solution, ammonia production and secretion rates were stimulated, in a losartan-inhibitable manner, to a greater extent in S3 segments from acidotic mice. Ammonia secretion rates in S3 segments were largely inhibited by perfusion with a low-sodium solution containing amiloride in the presence or absence of ANG II. These results demonstrated that isolated, perfused mouse S3 proximal tubule segments produce and secrete ammonia, that NH4Cl-induced acidosis does not affect the basal rates of ammonia production and secretion, and that ANG II, added to the luminal fluid, stimulates ammonia production and secretion to a greater extent in S3 segments from acidotic mice. These findings suggest that S3 segments, in the presence of ANG II, can contribute to the enhanced renal excretion that occurs with acid loading.

Interactions between angiotensin II and renal nerves during chronic sodium deprivation

1988 ◽  
Vol 255 (5) ◽  
pp. F823-F827 ◽  
Author(s):  
H. L. Mizelle ◽  
J. E. Hall ◽  
L. L. Woods
Keyword(s):  
Angiotensin Ii ◽  
Enzyme Inhibitor ◽  
Left Kidney ◽  
Control Period ◽  
Urine Volume ◽  
Renal Nerves ◽  
Ang Ii ◽  
Sodium Potassium ◽  
Low Sodium Diet ◽  
Low Sodium

The aim of this study was to examine the importance of the renal nerves in mediating the sodium-retaining actions of angiotensin II (ANG II) during chronic sodium deprivation. In seven female dogs the left kidney was denervated and the urinary bladder was split, allowing continuous urine collection from separate innervated and denervated kidneys in the same dog. The dogs were maintained on a low-sodium diet (7 meq/day) for 9 days and then infused with the converting-enzyme inhibitor captopril (CAP, 14 micrograms.kg-1.min-1, 7 days) followed by CAP plus ANG II (10 ng.kg-1.min-1, 7 days). Mean arterial pressure (MAP) fell from a control of 88 +/- 4 (average for 5 days preceding CAP) to 65 +/- 3 mmHg during CAP. Infusion of ANG II along with CAP restored MAP to 97 +/- 5 mmHg. There were no significant differences in urine volume or sodium, potassium, chloride, or osmolar excretions between innervated and denervated kidneys during the control period, CAP infusion, or CAP plus ANG II infusion. Norepinephrine content was reduced by 99 +/- 1% in denervated kidneys. Because a differential response was not observed between innervated and denervated kidneys during ANG II blockade or infusion of ANG II, we conclude that the renal nerves do not play a major role in mediating the sodium-retaining effects of ANG II during chronic sodium restriction.

Effect of angiotensin-converting enzyme inhibitor on salt appetite and thirst of BALB/c mice

1990 ◽  
Vol 259 (4) ◽  
pp. R736-R740 ◽  
Author(s):  
R. S. Weisinger ◽  
J. R. Blair-West ◽  
D. A. Denton ◽  
M. McBurnie ◽  
F. Ong ◽  
...  
Keyword(s):  
Food Intake ◽  
Angiotensin Converting Enzyme ◽  
Angiotensin Converting Enzyme Inhibitor ◽  
Water Intake ◽  
Low Dose ◽  
Enzyme Inhibitor ◽  
High Dose ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Converting Enzyme Inhibitor

The role of angiotensin II (ANG II) in Na-depletion-induced Na appetite of mice was investigated. Intraperitoneal injection of the angiotensin-converting enzyme inhibitor captopril at 1.7 mg/mouse (high dose) decreased the Na intake of the Na-depleted (furosemide-treated) mice by 80-85%. The decrease in Na intake was restored to the initial level by concurrent subcutaneous infusion of ANG II. High dose of captopril also decreased the Na intake of fluid-deprived, Na-depleted mice. High dose of captopril did not alter water intake in any of the four conditions examined, i.e., in fluid-replete, Na-depleted, water-deprived, or fluid-deprived, Na-depleted mice. Low dose of captopril (1.7 microgram/mouse) tended to or significantly enhanced Na intake of Na-depleted mice. Low dose of captopril, however, did not enhance water intake in any of the conditions examined. Both high- and low-dose captopril treatment decreased food intake in water-deprived mice, whether or not the mice were Na depleted as well. The addition of captopril (0.1 or 1.0 mg/ml) to the drinking water did not influence Na or food intake. Water intake was enhanced during treatment with the low but not with the high dose of captopril. The results are consistent with the proposition that ANG II is involved in the Na appetite of Na-depleted mice. ANG II does not appear to have a role in water intake of Na-depleted or water-deprived mice, but neural mechanisms in which angiotensin has a role may influence food intake of water-deprived mice.

Effect of cyclosporin on blood pressure and renin-aldosterone axis in rats

1987 ◽  
Vol 253 (6) ◽  
pp. H1596-H1600 ◽  
Author(s):  
S. Lustig ◽  
N. Stern ◽  
P. Eggena ◽  
M. L. Tuck ◽  
D. B. Lee
Keyword(s):  
Blood Pressure ◽  
Creatinine Clearance ◽  
Plasma Renin ◽  
Sodium Balance ◽  
Control Group ◽  
High Dose ◽  
Ang Ii ◽  
Aldosterone Secretion ◽  
Renin Substrate

Although hypertension is a frequent complication of cyclosporin A (CSA) therapy in clinical practice, little experimental information is available on the nature and the mechanism of this form of hypertension. We studied the effect of currently recommended therapeutic dosages of CSA, i.e., 5 (CSA5) and 20 (CSA20) mg.kg-1.day-1, on blood pressure and the renin-aldosterone system (RAS) in spontaneously hypertensive rats (SHR). Influence of in vivo CSA treatment on in vitro angiotensin II (ANG II)-stimulated aldosterone secretion by isolated adrenal glomerulosa cells (AGC) was also measured. CSA treatment in SHR resulted in a consistent increase in systolic blood pressure. This increase in blood pressure occurred in the absence of significant changes in creatinine clearance in CSA5 rats, whereas in CSA20 rats a significant reduction in creatinine clearance was observed. Sodium balance and serum calcium and magnesium concentrations were not different between the control group and either of the two CSA-treated groups of rats. Plasma renin concentration (PRC) and inactive renin (IR) were markedly elevated, but plasma renin substrate remained unchanged with CSA administration. Despite the presence of hyperreninemia, plasma aldosterone was not elevated, suggesting that CSA may induce relative adrenal resistance to ANG II. This possibility was tested using AGC isolated from CSA-treated rats. ANG II-stimulated aldosterone secretion in AGC was diminished by low dose and aborted by high dose CSA-treatment. Thus CSA administration in SHR induces a predictable increase in blood pressure in association with "hyperreninemic hypoaldosteronism."

Liver Histological Improvement After Administration of High-Dose Vitamin C in Guinea Pig with Nonalcoholic Steatohepatitis

2018 ◽  
Vol 88 (5-6) ◽  
pp. 263-269
Author(s):  
Seong-Hoon Park ◽  
A Lum Han ◽  
Na-Hyung Kim ◽  
Sae-Ron Shin
Keyword(s):  
Liver Biopsy ◽  
Vitamin C ◽  
Nonalcoholic Steatohepatitis ◽  
Guinea Pigs ◽  
Normal Diet ◽  
High Dose ◽  
Biochemical Tests ◽  
Deficient Diet ◽  
Histological Improvement ◽  
Vit C

Abstract. Background: Vitamin C is a strong antioxidant, and the health effects of vitamin C megadoses have not been validated despite the apparent health benefits. Therefore, the present study sought to confirm the effects of vitamin C megadoses. Materials and Methods : Four groups of six guinea pigs were used. Each group was fed one of the following diets for three weeks: normal diet, methionine choline-deficient diet, methionine choline-deficient diet + vitamin C megadose (MCD + vit C 2.5 g/kg/day), and methionine-choline deficient diet + ursodeoxycholic acid (MCD + UDCA 30 mg/kg/day). The MCD diet was given to induce nonalcoholic steatohepatitis, and UDCA was used to treat nonalcoholic steatohepatitis. Three weeks after initial diet administration, the results of biochemical tests and liver biopsy were compared between the groups. Results: The cytoplasm state was similar in the MCD + vit C and MCD + UDCA groups, exhibiting clearing of the cytoplasm and ballooning degeneration. However, macrovesicular steatosis was not observed in the MCD + vit C group. Aspartate transaminase and alanine transaminase were elevated significantly following vitamin C administration. Conclusions: The present study confirmed that alone vitamin C megadoses are potential remedies for nonalcoholic steatohepatitis, based on the liver biopsy results of guinea pigs that were unable to synthesize vitamin C.

scholarly journals Glycerol Monocaprylate Modulates Gut Microbiota and Increases Short-Chain Fatty Acids Production without Adverse Effects on Metabolism and Inflammation

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1427
Author(s):  
Junhui Zhang ◽  
Fengqin Feng ◽  
Minjie Zhao
Keyword(s):  
Fatty Acids ◽  
Gut Microbiota ◽  
Dose Group ◽  
Low Dose ◽  
Short Chain Fatty Acids ◽  
Normal Diet ◽  
Short Chain ◽  
High Dose ◽  
Dose Treatment ◽  
Chain Fatty Acids

Glycerol monocaprylate (GMC) is a glycerol derivative of medium-chain fatty acids (MCFAs) and is widely used as a preservative in food processing. However, GMC and its hydrolytic acid (octylic acid) have antibacterial properties that may affect the physiology and intestinal microecology of the human body. Therefore, in this study, the effects of two different dosages of GMC (150 and 1600 mg kg−1) on glucose, lipid metabolism, inflammation, and intestinal microecology of normal diet-fed C57BL/6 mice were comprehensively investigated. The obtained results showed that the level of triglycerides (TGs) in the low-dose group down-regulated significantly, and the anti-inflammatory cytokine interleukin 10 (IL-10) significantly increased, while the pro-inflammatory cytokines monocyte chemotactic protein 1 (MCP-1) and interleukin 1beta (IL-1β) in the high-dose group were significantly decreased. Importantly, GMC promoted the α-diversity of gut microbiota in normal-diet-fed mice, regardless of dosages. Additionally, it was found that the low-dose treatment of GMC significantly increased the abundance of Lactobacillus, while the high-dose treatment of GMC significantly increased the abundance of SCFA-producers such as Clostridiales, Lachnospiraceae, and Ruminococcus. Moreover, the content of short-chain fatty acids (SCFAs) was significantly increased by GMC supplementation. Thus, our research provides a novel insight into the effects of GMC on gut microbiota and physiological characteristics.

scholarly journals Angiotensin II stimulates trafficking of NHE3, NaPi2, and associated proteins into the proximal tubule microvilli

2010 ◽  
Vol 298 (1) ◽  
pp. F177-F186 ◽  
Author(s):  
Anne D. M. Riquier-Brison ◽  
Patrick K. K. Leong ◽  
Kaarina Pihakaski-Maunsbach ◽  
Alicia A. McDonough
Keyword(s):  
Angiotensin Ii ◽  
Proximal Tubule ◽  
Flow Rate ◽  
Enzyme Inhibitor ◽  
Volume Flow Rate ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Water Reabsorption ◽  
Associated Proteins ◽  
Gradient Fractionation

Angiotensin II (ANG II) stimulates proximal tubule (PT) sodium and water reabsorption. We showed that treating rats acutely with the angiotensin-converting enzyme inhibitor captopril decreases PT salt and water reabsorption and provokes rapid redistribution of the Na+/H+ exchanger isoform 3 (NHE3), Na+/Pi cotransporter 2 (NaPi2), and associated proteins out of the microvilli. The aim of the present study was to determine whether acute ANG II infusion increases the abundance of PT NHE3, NaPi2, and associated proteins in the microvilli available for reabsorbing NaCl. Male Sprague-Dawley rats were infused with a dose of captopril (12 μg/min for 20 min) that increased PT flow rate ∼20% with no change in blood pressure (BP) or glomerular filtration rate (GFR). When ANG II (20 ng·kg−1·min−1 for 20 min) was added to the captopril infusate, PT volume flow rate returned to baseline without changing BP or GFR. After captopril, NHE3 was localized to the base of the microvilli and NaPi2 to subapical cytoplasmic vesicles; after 20 min ANG II, both NHE3 and NaPi2 redistributed into the microvilli, assayed by confocal microscopy and density gradient fractionation. Additional PT proteins that redistributed into low-density microvilli-enriched membranes in response to ANG II included myosin VI, DPPIV, NHERF-1, ezrin, megalin, vacuolar H+-ATPase, aminopeptidase N, and clathrin. In summary, in response to 20 min ANG II in the absence of a change in BP or GFR, multiple proteins traffic into the PT brush-border microvilli where they likely contribute to the rapid increase in PT salt and water reabsorption.

scholarly journals A first-in-human, phase 1 study of the NEDD8 activating enzyme E1 inhibitor TAS4464 in patients with advanced solid tumors

2021 ◽  
Author(s):  
Noboru Yamamoto ◽  
Toshio Shimizu ◽  
Kan Yonemori ◽  
Shigehisa Kitano ◽  
Shunsuke Kondo ◽  
...  
Keyword(s):  
Liver Function ◽  
Solid Tumors ◽  
Dose Escalation ◽  
Enzyme Inhibitor ◽  
Phase 1 ◽  
Maximum Tolerated Dose ◽  
Primary Objective ◽  
Open Label ◽  
Phase 1 Study ◽  
Open Label Phase

SummaryBackground This open-label, phase 1 study investigated TAS4464, a potent NEDD8-activating enzyme inhibitor, in patients with advanced/metastatic solid tumors (JapicCTI-173,488; registered 13/01/2017). The primary objective was dose-limiting toxicities (DLTs). Maximum-tolerated dose (MTD) was investigated using an accelerated titration design. Methods The starting 10-mg/m2 dose was followed by an initial accelerated stage (weekly dosing; n = 11). Based on liver function test (LFT) results, a 14-day, 20-mg/m2 dose lead-in period was implemented (weekly dosing with lead-in; n = 6). Results Abnormal LFT changes and gastrointestinal effects were the most common treatment-related adverse events (AEs). DLTs with 56-mg/m2 weekly dosing occurred in 1/5 patients; five patients had grade ≥ 2 abnormal LFT changes at 40- and 56-mg/m2 weekly doses. Further dose escalation ceased because of the possibility of severe abnormal LFT changes occurring. DLTs with weekly dosing with lead-in occurred in 1/5 patients at a 56-mg/m2 dose; MTD could not be determined because discontinuation criteria for additional enrollment at that particular dose level were met. As no further enrollment at lower doses occurred, dose escalation assessment was discontinued. Serious treatment-related AEs, AEs leading to treatment discontinuation, and DLTs were all related to abnormal LFT changes, suggesting that TAS4464 administration could affect liver function. This effect was dose-dependent but considered reversible. Complete or partial responses to TAS4464 were not observed; one patient achieved prolonged stable disease. Conclusions MTD could not be determined due to TAS4464 effects on liver function. Further evaluation of the mechanism of NEDD8-activating enzyme inhibitor-induced abnormal liver function is required. Trial registration number JapicCTI-173,488 (registered with Japan Pharmaceutical Information Center). Registration date 13 January 2017

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