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American Journal of Physiology. Renal... Jun 2020We characterized mouse blood pressure and ion transport in the setting of commonly used rodent diets that drive K intake to the extremes of deficiency and excess. Male... (Comparative Study)
Comparative Study
We characterized mouse blood pressure and ion transport in the setting of commonly used rodent diets that drive K intake to the extremes of deficiency and excess. Male 129S2/Sv mice were fed either K-deficient, control, high-K basic, or high-KCl diets for 10 days. Mice maintained on a K-deficient diet exhibited no change in blood pressure, whereas K-loaded mice developed an ~10-mmHg blood pressure increase. Following challenge with NaCl, K-deficient mice developed a salt-sensitive 8 mmHg increase in blood pressure, whereas blood pressure was unchanged in mice fed high-K diets. Notably, 10 days of K depletion induced diabetes insipidus and upregulation of phosphorylated NaCl cotransporter, proximal Na transporters, and pendrin, likely contributing to the K-deficient NaCl sensitivity. While the anionic content with high-K diets had distinct effects on transporter expression along the nephron, both K basic and KCl diets had a similar increase in blood pressure. The blood pressure elevation on high-K diets correlated with increased Na-K-2Cl cotransporter and γ-epithelial Na channel expression and increased urinary response to furosemide and amiloride. We conclude that the dietary K maneuvers used here did not recapitulate the inverse effects of K on blood pressure observed in human epidemiological studies. This may be due to the extreme degree of K stress, the low-Na-to-K ratio, the duration of treatment, and the development of other coinciding events, such as diabetes insipidus. These factors must be taken into consideration when studying the physiological effects of dietary K loading and depletion.
Topics: Animal Feed; Animals; Arterial Pressure; Diabetes Insipidus; Epithelial Sodium Channels; Hypertension; Ion Transport; Kidney Tubules; Male; Mice, 129 Strain; Natriuresis; Phosphorylation; Potassium Deficiency; Potassium, Dietary; Sodium Chloride Symporters; Sodium Chloride, Dietary; Sodium-Potassium-Chloride Symporters; Sulfate Transporters
PubMed: 32281415
DOI: 10.1152/ajprenal.00527.2019 -
Journal of the American College of... Jun 2006Compared with the Stone Age diet, the modern human diet is both excessive in NaCl and deficient in fruits and vegetables which are rich in K+ and HCO3- -yielding...
Compared with the Stone Age diet, the modern human diet is both excessive in NaCl and deficient in fruits and vegetables which are rich in K+ and HCO3- -yielding organates like citrate. With the modern diet, the K+/Na+ ratio and the HCO3-/Cl- ratio have both become reversed. Yet, the biologic machinery that evolved to process these dietary electrolytes remains largely unchanged, genetically fixed in Paleolithic time. Thus, the electrolytic mix of the modern diet is profoundly mismatched to its processing machinery. Dietary potassium modulates both the pressor and hypercalciuric effects of the modern dietary excess of NaCl. A marginally deficient dietary intake of potassium amplifies both of these effects, and both effects are dose-dependently attenuated and may be abolished either with dietary potassium or supplemental KHCO3. The pathogenic effects of a dietary deficiency of potassium amplify, and are amplified by, those of a dietary excess of NaCl and in some instances a dietary deficiency of bicarbonate precursors. Thus, in those ingesting the modern diet, it may not be possible to discern which of these dietary electrolytic dislocations is most determining of salt-sensitive blood pressure and hypercalciuria, and the hypertension, kidney stones, and osteoporosis they may engender. Obviously abnormal plasma electrolyte concentrations rarely characterize these dietary electrolytic dislocations, and when either dietary potassium or supplemental KHCO3 corrects the pressor and hypercalciuric effects of these dislocations, the plasma concentrations of sodium, potassium, bicarbonate and chloride change little and remain well within the normal range.
Topics: Acid-Base Imbalance; Animals; Bicarbonates; Blood Pressure; Diet; Humans; Kidney; Kidney Calculi; Potassium, Dietary; Sodium, Dietary; Water-Electrolyte Balance
PubMed: 16772638
DOI: 10.1080/07315724.2006.10719576 -
Biosensors & Bioelectronics May 2018This paper presents the demonstration of on-chip fabrication of a potassium-selective sensor array enabled by electrowetting on dielectric digital microfluidics for the...
This paper presents the demonstration of on-chip fabrication of a potassium-selective sensor array enabled by electrowetting on dielectric digital microfluidics for the first time. This demonstration proves the concept that electrochemical sensors can be seamlessly integrated with sample preparation units in a digital microfluidic platform. More significantly, the successful on-chip fabrication of a sensor array indicates that sensors become reconfigurable and have longer lifetime in a digital microfluidic platform. The on-chip fabrication of ion-selective electrodes includes electroplating Ag followed by forming AgCl layer by chemical oxidation and depositing a thin layer of desired polymer-based ion selective membrane on one of the sensor electrodes. In this study, potassium ionophores work as potassium ion channels and make the membrane selective to potassium ions. This selectiveness results in the voltage difference across the membrane layer, which is correlated with potassium ion concentration. The calibration curve of the fabricated potassium-selective electrode demonstrates the slope of 58 mV/dec for potassium concentration in KCl sample solutions and shows good agreement with the ideal Nernstian response. The proposed sensor platform is an outstanding candidate for a portable home-use for continuous monitoring of ions thanks to its advantages such as easy automation of sample preparation and detection processes, elongated sensor lifetime, minimal membrane and sample consumption, and user-definable/reconfigurable sensor array.
Topics: Biosensing Techniques; Electrochemical Techniques; Ions; Microfluidics; Polymers; Potassium; Silver Compounds
PubMed: 29414086
DOI: 10.1016/j.bios.2018.01.048 -
Journal of Insect Physiology Jan 2019Excretion of metabolic wastes and toxins in insect Malpighian tubules (MTs) is coupled to secretion of ions and fluid. Larval lepidopterans demonstrate a complex and...
Excretion of metabolic wastes and toxins in insect Malpighian tubules (MTs) is coupled to secretion of ions and fluid. Larval lepidopterans demonstrate a complex and regionalized MT morphology, and recent studies of larvae of the cabbage looper, Trichoplusia ni, have revealed several unusual aspects of ion transport in the MTs. Firstly, cations are reabsorbed via secondary cells (SCs) in T. ni, whereas in most insects SCs secrete ions. Secondly, SCs are coupled to neighbouring principal cells (PCs) via gap junctions to enable such ion reabsorption. Thirdly, PCs in the SC-containing distal ileac plexus (DIP) region of the tubule reverse from cation secretion to reabsorption in response to dietary ion loading. Lastly, antidiuresis is observed in response to a kinin neuropeptide, which targets both PCs and SCs, whereas in most insects kinins are diuretics that act exclusively via SCs. Recent studies have generated a basic model of ion transport in the DIP of the larval T. ni. RNAseq was used to elucidate previously uncharacterised aspects of ion transport and endocrine regulation in the DIP, with the aim of painting a composite picture of ion transport and identifying putative regulatory mechanisms of ion transport reversal in this tissue. Results indicated an overall expression of 9103 transcripts in the DIP, 993 and 382 of which were differentially expressed in the DIP of larvae fed high-K and high-Na diets respectively. Differentially expressed transcripts include ion-motive ATPases, ion channels and co-transporters, aquaporins, nutrient and xenobiotic transporters, cell adhesion and junction components, and endocrine receptors. Notably, several transcripts for voltage-gated ion channels and cell volume regulation-associated products were detected in the DIP and differentially expressed in larvae fed ion-rich diet. The study provides insights into the transport of solutes (sugars, amino acids, xenobiotics, phosphate and inorganic ions) by the DIP of lepidopterans. Our data suggest that this region of the MT in lepidopterans (as previously reported) transports cations, fluid, and xenobiotics/toxic metals. Besides this, the DIP expresses genes coding for the machinery involved in Na- and H-dependent reabsorption of solutes, chloride transport, and base recovery. Additionally, many of the transcripts expressed by the DIP a capacity of this region to respond to, process, and sometimes produce, neuropeptides, steroid hormones and neurotransmitters. Lastly, the DIP appears to possess an arsenal of septate junction components, differential expression of which may indicate junctional restructuring in the DIP of ion-loaded larvae.
Topics: Absorption, Physiological; Animals; Ion Channels; Ion Transport; Malpighian Tubules; Moths; Potassium, Dietary; Sodium, Dietary; Transcriptome
PubMed: 30562492
DOI: 10.1016/j.jinsphys.2018.12.005 -
Canadian Medical Association Journal Jan 1962
Topics: Humans; Hypertension; Ions; Potassium; Sodium; Sodium, Dietary
PubMed: 14488753
DOI: No ID Found -
Kidney International Feb 1997
Review
Topics: Acidosis; Acquired Immunodeficiency Syndrome; Adult; Aldosterone; Animals; Chlorides; Disease Models, Animal; Female; Humans; Hyperkalemia; Ion Transport; Kidney; Kidney Failure, Chronic; Mineralocorticoids; Nephrons; Potassium; Potassium, Dietary; Quaternary Ammonium Compounds
PubMed: 9027745
DOI: 10.1038/ki.1997.85 -
The American Journal of Physiology Nov 1986To determine the effect of variations in body stores of potassium on the rate of active potassium transport in the large intestine, unidirectional 42K fluxes were...
To determine the effect of variations in body stores of potassium on the rate of active potassium transport in the large intestine, unidirectional 42K fluxes were performed under short-circuit conditions across isolated distal colonic mucosa of control, dietary potassium-depleted and dietary potassium-loaded rats. Potassium depletion stimulated net potassium absorption (JK net) (0.87 +/- 0.19 vs. 0.49 +/- 0.04 mu eq X h-1 X cm-2, P less than 0.025) due to a 40% increase in mucosal-to-serosal potassium transport (JK m----s). In sodium-free Ringer solution JK net in the potassium-depleted group was also significantly greater than in controls (1.93 +/- 0.26 vs. 1.01 +/- 0.11 mu eq X h-1 X cm-2, P less than 0.005). In contrast, in chloride-free Ringer solution JK net was identical in the control and potassium-depleted groups (0.39 +/- 0.05 vs. 0.46 +/- 0.07 mu eq X h-1 X cm-2, P = NS). Potassium loading reversed net potassium absorption to net potassium secretion (-0.76 +/- 0.08 mu eq X h-1 X cm-2, P less than 0.001) as the result of a decrease in JK m----s and an increase in serosal-to-mucosal potassium transport (JK s----m). Net potassium secretion was abolished in the absence of either sodium or chloride from the bathing solution but not by mucosal amiloride. In sodium-free Ringer solution JK net was similar in control and potassium-loaded groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Amiloride; Animals; Biological Transport, Active; Colon; Diet; Intestinal Absorption; Kinetics; Male; Potassium; Protons; Rats; Rats, Inbred Strains; Sodium
PubMed: 3022598
DOI: 10.1152/ajpgi.1986.251.5.G619 -
Journal of Dairy Science Jul 2012The effect of additional dietary potassium in early lactation dairy cows was evaluated with the addition of potassium carbonate sesquihydrate, which increased dietary K...
The effect of additional dietary potassium in early lactation dairy cows was evaluated with the addition of potassium carbonate sesquihydrate, which increased dietary K from 1.3 to 2.1% of dry matter (DM) from wk 3 to 12 of lactation. Cows fed potassium carbonate sesquihydrate in the form of DCAD Plus (Church & Dwight Co. Inc., Princeton, NJ) had increased DM intake, milk fat percentage and yield, energy-corrected milk, and efficiency of milk production per unit of DM intake. Milk fat of cows fed higher dietary K had a lower concentration of trans fatty acids, suggesting a role for potassium carbonate sesquihydrate in the rumen in the biohydrogenation processes converting linoleic to stearic acid. Cows fed the diet with 2.1% K had greater apparent balance of K, and no effects were noted on the concentration of blood Mg or amount of fecal Mg. The data support the feeding of greater amounts of K in the early lactation cow.
Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Carbonates; Cattle; Diet; Dietary Supplements; Eating; Fats; Female; Hydrogenation; Lactation; Milk; Milk Proteins; Potassium; Potassium, Dietary; Rumen
PubMed: 22720946
DOI: 10.3168/jds.2011-4840 -
Current Opinion in Nephrology and... Sep 2011Recent studies have provided compelling evidence that tissue kallikrein exerts kinin-independent effects on several renal transporters including the epithelial Na⁺... (Review)
Review
PURPOSE OF REVIEW
Recent studies have provided compelling evidence that tissue kallikrein exerts kinin-independent effects on several renal transporters including the epithelial Na⁺ channel (ENaC), the epithelial calcium channel TRPV5 (transient receptor potential channel vanilloid subtype 5), and the colonic H⁺,K⁺-ATPase. This review focuses on the role of tissue kallikrein in the regulation of renal sodium and potassium handling.
RECENT FINDINGS
Tissue kallikrein is a serine protease involved in the generation of kinins in many organs including the kidney, and most of the renal tissue kallikrein function involves its ability to generate kinins. Tissue kallikrein, through its catalytic activity, acts directly on ENaC in order to modulate its activity but is not critical for the regulation of renal sodium homeostasis. Tissue kallikrein deficient mice exhibit net transepithelial K⁺ absorption in cortical collecting ducts because of abnormal activation of the colonic H⁺,K⁺-ATPase in intercalated cells and reduced K⁺ secretion by principal cells secondary to decreased ENaC activity. Tissue kallikrein is a kaliuretic factor that provides a rapid and aldosterone-independent protection against hyperkalemia after a dietary K⁺load.
SUMMARY
Tissue kallikrein produced by connecting tubule cells regulates apical transporters by acting from the tubular lumen. Studies have demonstrated the existence of autocrine/paracrine regulatory mechanisms of K⁺ transport in the distal nephron.
Topics: Animals; Epithelial Cells; Epithelial Sodium Channels; H(+)-K(+)-Exchanging ATPase; Homeostasis; Humans; Hyperkalemia; Ion Transport; Kidney Tubules; Potassium; Potassium, Dietary; Sodium; Tissue Kallikreins
PubMed: 21709551
DOI: 10.1097/MNH.0b013e328348d4af -
Physiological Genomics Sep 2004Plasticity of mouse renal collecting duct in response to potassium depletion.--Renal collecting ducts are the main sites for regulation of whole body potassium balance....
Plasticity of mouse renal collecting duct in response to potassium depletion.--Renal collecting ducts are the main sites for regulation of whole body potassium balance. Changes in dietary intake of potassium induce pleiotropic adaptations of collecting duct cells, which include alterations of ion and water transport properties along with an hypertrophic response. To study the pleiotropic adaptation of the outer medullary collecting duct (OMCD) to dietary potassium depletion, we combined functional studies of renal function (ion, water, and acid/base handling), analysis of OMCD hypertrophy (electron microscopy) and hyperplasia (PCNA labeling), and large scale analysis of gene expression (transcriptome analysis). The transcriptome of OMCD was compared in mice fed either a normal or a potassium-depleted diet for 3 days using serial analysis of gene expression (SAGE) adapted for downsized extracts. SAGE is based on the generation of transcript-specific tag libraries. Approximately 20,000 tags corresponding to 10,000 different molecular species were sequenced in each library. Among the 186 tags differentially expressed (P < 0.05) between the two libraries, 120 were overexpressed and 66 were downregulated. The SAGE expression profile obtained in the control library was representative of different functional classes of proteins and of the two cell types (principal and alpha-intercalated cells) constituting the OMCD. Combined with gene expression analysis, results of functional and morphological studies allowed us to identify candidate genes for distinct physiological processes modified by potassium depletion: sodium, potassium, and water handling, hyperplasia and hypertrophy. Finally, comparison of mouse and human OMCD transcriptomes allowed us to address the question of the relevance of the mouse as a model for human physiology and pathophysiology.
Topics: Acid-Base Equilibrium; Adaptation, Physiological; Animals; Body Weight; Gene Expression Profiling; Humans; Hyperplasia; Hypertrophy; Kidney Tubules, Collecting; Male; Mice; Mice, Inbred C57BL; Organ Size; Potassium Deficiency; Potassium, Dietary; Proliferating Cell Nuclear Antigen; RNA, Messenger; Reproducibility of Results; Transcription, Genetic
PubMed: 15238618
DOI: 10.1152/physiolgenomics.00055.2004