Tissue Potassium Content Research Articles

Effect of sodium in the nutrient medium on the incidence of potassium-deficiency symptoms in tomato plants

Tomato plants (Lycopersicon esculentum cv. Amberley Cross) were grown in sand culture and were fed with four concentrations of potassium nitrate in combination with two levels of sodium nitrate. After six weeks the plants were scored for the presence and absence of a symptom of potassium deficiency, namely, marginal chlorosis and/or necrosis in the young, fully-expanded leaves. These leaves were also analysed for K and Na. Marginal chlorosis and/or necrosis occurred in plants given a nutrient solution containing 0.5 meq K/I or less and supplied with either of the sodium nitrate levels. However, the symptoms occurred more frequently in plants receiving the lower level of sodium nitrate. The laminae on plants receiving the lower concentration of sodium nitrate had a 50 per cent incidence of chlorisis and/or necrosis when the tissue potassium content was 0.74 per cent of the dry wt, while those laminae on plants receiving the higher level did not show a 50 per cent incidence until their potassium fell to 0.64 per cent of the dry wt.

Ouabain and regulation of cellular volume in freshly prepared slices of rabbit renal cortex.

1. Changes in the water and ion contents of rabbit renal cortical slices, which had been bathed, immediately after slicing, in air-equilibrated media at room temperature ('freshly prepared slices'), were followed during subsequent incubation at 25 degrees C in oxygenated media of the same composition as the initial bathing medium. 2. In comparison with conventional 'equilibrated' slices (slices incubated at 25 degrees C in oxygenated ordinary medium immediately after slicing) these 'freshly prepared' slices had increased tissue water, sodium and chloride contents and low tissue potassium contents. 3. Control freshly prepared slices incubated at 25 degrees C in oxygenated ordinary medium recovered within 4 min to the tissue water content that is usual for rabbit renal cortical slices incubated in oxygenated ordinary medium at 25 degrees C. Freshly prepared slices incubated at 25 degrees C in oxygenated media containing 1 mM-oubain took 75 min or more to recover to this usual tissue water content. Thus the presence of 1 mM-oubain in both bathing and incubation media produced a marked inhibition of the volume recovery observed when freshly prepared slices are incubated in oxygenated media at 25 degrees C. 4. Reduction of the ouabain concentration reduced the inhibition of cell volume recovery. 5. Replacement of medium glucose by 3-O-methylglucose did not inhibit cell volume recovery in the absence of ouabain. 6. The oxygen consumptions of slices that were bathed and incubated in 1 mM-ouabain media were similar to those of slices initially bathed and incubated in ouabain-free media and then incubated in ouabain media. Thus the effect of ouabain in inhibiting cell volume recovery was unlikely to be secondary to inhibition of cellular energy production. 7. The tissue potassium content of slices incubated aerobically in 1 or 10 mM ouabin fell to an apparently stable value of approximately 100 m-mole/kg dry wt., which corresponds to a calculated concentration ratio of 10:1 across the cellular membrane, suggesting that some residual potassium uptake may still have been occurring. 8. These results indicate that in freshly prepared rabbit renal cortical slices ouabain-sensitive mechanisms play a major role in cell volume recovery. They are not in accord with the postulate that renal cortical cells possess a separate ouabain-insensitive mechanism regulating cell volume.

Effects of ouabain and potassium-free media on cellular volume regulation in rat renal cortical slices.

1. Changes in water and ion contents of rat renal cortical slices were followed over 4 hr incubation at 25 degrees C in potassium-free media and media with ouabain. Slices that lost potassium more rapidly swelled earlier. 2. Greater swelling with lower tissue potassium contents was also observed in slices preincubated and leached in potassium-depleting media and in slices incubated in lithium medium with 10 mM-ouabain and in potassium-free lithium medium with 10 mM-ouabain. 3. This swelling associated with potassium depletion was also observed when slices were incuabted in media where the substrate was malate in place of glucose. 4. No distinct fall in the oxygen consumption of potassium-depleted slices was detected during the period in which slices commenced swelling. 5. These results suggest that the swelling observed in potassium-depleted rat renal cortical slices is unlikely to be secondary to inhibition of cellular energy production.

Further studies on the relationship between potassium and sodium levels and adrenocortical activity.

Steroid production in vitro by dog adrenal cortical slices was measured in the presence of varying concentrations of sodium and potassium ions. Increasing concentrations of potassium produced a significant increase in the intracellular potassium content and in the rate of synthesis of aldosterone. However, the potassium effect on aldosterone secretion may also occur without changes in tissue potassium content. Ouabain significantly diminished intracellular potassium content, but inhibited aldosterone production only at the high dose of 2.5 X 10(-3) M in the presence of an elevated external potassium level. Physiological changes in sodium concentration can modify aldosterone production. The effect was observed with changes as small as 10 mEq/liter sodium. Changes in external potassium and sodium levels modulate aldosterone as well as corticosterone, but not cortisol production. No changes in the intracellular content of potassium were detectable in angiotensin-stimulated tissue. Nevertheless, high doses of ouabain blocked angiotensin-stimulated aldosterone production without affecting cortisol production. The dissociation observed between intracellular potassium levels and aldosterone production suggests that there is not a simple relationship between the two parameters.

Response of cassava, sunflower, and maize to potassium concentration in solution I. Growth and plant potassium concentration

Twelve cultivars of cassava and one cultivar each of sunflower and maize were grown for 27 days at eight constant solution potassium concentrations ranging from 0.5 to 8024 μM. All species and cultivars required a minimum solution concentration of 2 to 6 μM K to produce maximum yield. At solution potassium concentrations greater than 122 μM the yield of most cassava cultivars declined and at 8024 μM K all cultivars displayed magnesium deficiency symptoms. A limited variation among species and cultivars was observed in the minimum tissue concentration necessary for healthy growth. Large differences in dry matter percentage existed among species, plant parts and potassium treatments. Because of these differences, trends in potassium concentration expressed on a dry weight basis in some instances did not accurately reflect trends in potassium concentration in the fresh tissue. Although all three species produced maximum dry matter yield at similar solution potassium concentrations, at suboptimal concentrations cassava regulated its growth more successfully in relation to potassium supply than did sunflower or maize. At 0.5 μM K cassava continued to grow slowly with less reduction in relative yield, less pronounced deficiency symptoms and a smaller gradient in tissue potassium concentrations from older to younger leaves than the other species. Continued slow growth of cassava at low solution potassium concentrations was aided by greater increase in the relative size of the root system.

Relations entre la fertilisation et la concentration des nitrates et du potassium dans les feuilles et le rendement et la qualite du mais de table

Abstract Twenty sweet corn tissue samplings were made from ten field trials during 1974–76. Fertilization had little effect on yields, but a good relationship was found between yields and leaf tissue nitrate and potassium concentrations, in the leaves 40–50 percent developed at the F‐9, F‐13 and F‐14 vegetative stages. The lower and upper tissue nitrate and potassium concentration limits (deficiency and excess) were found to range between 2000 and 3000 ppm nitrate, and 1.5 and 4.2 percent, or 2.0 and 3.25 percent potassium, according to their vegetative development. Excessive nitrogen and phosphorus application decreased kernel tenderness and total solids (sugar) content, but potassium fertilization enhanced total sugar accumulation.

Lower Sphincter of the Opossum Esophagus in Pseudopregnancy

To seek a possible role of estrogen and progesterone in the development of changes in esophageal function during pregnancy, we produced a state of pseudopregnancy by administration of hormones to a suitable animal model. Twenty-two female opossums weighing an average of 2.5 kg, were divided into two groups. The treated group received intramuscular injections of 100 microgram of estradiol valerate daily from day 1 to day 12 and 15 mg of medroxyprogesterone acetate from day 7 to day 12. The control group received no injections. Both groups underwent manometry on days 1, 7, and 12. Lower esophageal sphincter pressure decreased (P less than 0.05) in treated animals from 58 +/- 13 mm Hg and 57 +/- 11 on days 1 and 7, respectively, to 44 +/- 10 mm Hg on day 12. The lower esophageal sphincter pressure remained unchanged in control animals. In both groups, there was no change in peristaltic wave pressure, duration, or velocity in the distal 6 cm of the esophagus. No abnormal peristaltic phenomena were observed. Esophageal muscle strips prepared from treated animals showed responses to electrical field stimulation of intrinsic nerves that were like those from control animals. The same was true for responses to acetylcholine and pentagastrin. Total tissue water and total tissue potassium content did not differ in treatment and control animals.

Potassium reaccumulation by isolated frog epidermis

The involvement of potassium in transepithelial sodium transport was tested by studying net potassium reuptake by potassium-depleted frog skin epidermis. Normal potassium content in half-strength Ringer's (0.244 μequiv/mg dry weight) fell 43% after 16 h in K-free medium at 5°C. Reaccumulation, against an electrochemical potential gradient, to 83% of the initial tissue potassium content occurred following incubation for 4 h at 22°C in K-containing medium. Sodium was required in the solution bathing the inside, but not the outside surface of the skin, for net potassium reaccumulation. Ouabain caused an additional potassium loss from potassium-depleted epidermis, but did not have the same effect on potassium-depleted isolatedcells. Procaine, lithium and caffeine completely inhibited, antidiuretic hormone and cyclic AMP may partially inhibit and amiloride had no effect on potassium reaccumulation. In many cases decreases in sodium and water content were found to occur even in the absence of net potassium reaccumulation. The results suggest (1) potassium is actively transported into the epidermis, (2) this transport is not rigidly coupled to sodium extrusion or water loss, (3) potassium uptake is not rigidly coupled to transepithelial sodium transport, or only a small fraction is involved, (4) potassium diffusion is restricted in the extracellular space.

A potassium gradient in smooth muscle segment of the opossum esophagus.

Sodium and potassium content were determined in the smooth muscle segment of the opossum esophagus. Extracellular space measurements were also made using inulin and mannitol as markers. The muscle also made using inulin and mannitol as markers. The muscle was sampled at five sites spaced equally along the esophageal segment. On site in the stomach was also examined. The mean tissue sodium content was 36.6 +/- 10.7 meg/kg, and the mean tissue sodium content was 83.5 +/- 2.9 meg/kg wet wt. The mean inulin space was 184 +/- 34 ml/kg, and the mean mannitol space was 249 +/- 20 ml wet wt. The tissue potassium content was found to decline from 48.4 /- 10.1 meg/kg at the proximal site to 23.6 +/- 8.0 meg k/g at the distal site. The slope of electrolyte values from sites 1 through 5 was significant for both potassium and sodium. Extracellular space volume did not differ significantly from one end of the smooth muscle segment to the other.

Effect of potassium on utilization of (1-14C)palmitic acid in renal cortex of the rat.

The renal cortex has an unusually high rate of palmitic acid utilization. The uptake, oxidation, and distribution of this fatty acid in the cortex, unlike other tissues, responds to variations in medium and tissue potassium content. This potassium dependency is mimicked and amplified by rubidium. These observations indicate that in the renal cortex, both potassium and rubidium promote the accumulation, oxidation, and esterification of palmitic acid.

Individual Plant Variability in Susceptibility to Potassium Deficiency: Some Observations on Capeweed [Arctotheca calendula (L.) Levyns

Individual plants in an apparently uniform set of capeweed seedlings were found to differ markedly in susceptibility to potassium deficiency when grown in solution culture at a constant potassium concentration of 2.6 �M. Large differences were found in dry weight of tops (8-218 mg), tissue potassium concentration (0.3 - 4.8 %) and total potassium in the tops (23-10 500 �g potassium). Dry weight and percentage potassium were positively correlated (r = 0.859, P<0.001) at 2.6 �M potassium but not at higher potassium concentrations. The nature and possible exploitation of such variability in cross-fertilized forage plants are briefly discussed.

Influence of oxygen and glucose on the water and ion content of swine aorta.

The swelling properties of isolated swine arterial tissue have been studied to determine their effect on diffusion and hydraulic permeability measurements. Tissue potassium and sodium content were also measured to obtain an index of tissue metabolic activity. When oxygen and glucose were present in the incubation medium, a 5% decrease in tissue water content was observed over an incubation period of approximately 3.5 h. Under these conditions the tissue potassium content was higher and the sodium content was lower than when oxygen and/or glucose were omitted from the medium. When both oxygen and glucose were omitted, the potassium and sodium levels were significantly altered, suggesting a disturbance in the sodium-potassium transport system due to depletion of necessary metabolities.

Effects of exposure to sublethal levels of cadmium upon water‐electrolyte status in the goldfish (Carassius auratus)

Goldfish were exposed to sublethal levels of cadmium (means of 44.5 and 380 μg Cd++/l) for periods of 25 and 50 days, and their water‐electrolyte status evaluated by reference to plasma and muscle levels of sodium, potassium and chloride and muscle water content. Significant changes in plasma chloride, tissue potassium and tissue water content were observed after 25 days in both test solutions. Specimens held at the more dilute cadmium concentration were apparently able to compensate for most of the initial cadmium effect and, after 50 days exposure, were characterized only by a continuing depression in plasma sodium level. This suggests that the cadmium MATC value for this species under the conditions employed is probably less than 45 μg Cd++/l. Goldfish exposed to 380 μg Cd++/l for 50 days exhibited significant deviations in plasma sodium and chloride levels as well as in tissue sodium and water content, and these parameters may provide useful indices of cadmium effects at sublethal concentrations.

Regulation of citrate metabolism by cell pH in potassium-depleted rat diaphragm

Regulation of citrate metabolism by cell pH in potassium-depleted rat diaphragm. It is unknown whether metabolic changes occurring in potassium deficiency are due to altered cell pH or to decreased tissue potassium. To study this problem intact rat diaphragms were acutely potassium-depleted in vitro , cell pH was calculated using DMO distribution and the cell pH and citrate metabolism of these tissues was compared to the same measurements made in diaphragms not potassium-depleted. Potassium depletion had no significant effect on either cell pH or citrate decarboxylation when extracellular pH was 7.40. By contrast, in extracellular metabolic acidosis (pH, 6.90), cell pH was lower in potassium-depleted diaphragms, citrate decarboxylation was higher and muscle citrate concentration was reduced. However, in metabolic acidosis, when extracellular pH in diaphragms not potassium-depleted was made lower than in potassium-depleted tissue, cell pH became identical in the two groups and the differences in citrate decarboxylation and citrate concentration disappeared. Thus, at the same cell pH, citrate metabolism in muscle was identical despite marked differences in tissue potassium. These experiments indicate that the changes in muscle citrate metabolism found in potassium depletion are due to potassium-induced changes in cell pH and are not due to the lower tissue potassium concentration itself.

Effects of prostaglandins PGE 1 and PGF 2 alpha on oxygen consumption, sodium and potassium content of renal tissue.

Chez le rat la prostaglandine E1 augmente la consommation d'oxygene et la teneur en potassium, tandis qu'elle abaisse la teneur en sodium dans le tissu renal et hepatique. On y a observe une correlation entre l'effet et la dose de PGE1 employee. Cependant dans les coupes du tissu hepathique, la PGE1 est restee sans action. A meme dose la PGF2α a produit des effets comparables a ceux qu'on obtient avec la PGE1. Ces resultats indiqueraient que la reponse natriuretique a la PGE1 ne semble pas due a une inhibition de la “pompe” de sodium des cellules tubulaires, mais a une elevation du flux sanguin renal.

Cerebral water and electrolytes. An experimental model of inappropriate secretion of antidiuretic hormone.

Administration of fluid and vasopressin injection to rats induced within 24 to 48 hours a condition which can be considered as an experimental model of the syndrome of inappropriate secretion of antidiuretic hormone (ADH). Concurrently with hyponatremia and hypoosmolarity in serum, the changes in muscle consisted of a fall in sodium content and a decrease in percentage dry weight equivalent to 12% swelling. There was no loss of potassium from muscle. In contrast, in brain the decrease in sodium content was smaller, the tissue percentage dry weight decreased only slightly, indicating minimal swelling, and there was a significant net loss of potassium. It is suggested that neurological dysfunction associated with the syndrome of inappropriate secretion of ADH is unlikely to be due to cerebral edema but may be related to the decreased potassium content of brain tissue.

AVAILABLE SOIL POTASSIUM AND FERTILIZER POTASSIUM FOR BRUSSELS SPROUTS

Brussels sprouts (Brassica oleracea var. gemmifera DC., Jade Cross) require no potassium fertilizer on Prince Edward Island soils if exchangeable soil K as determined by neutral 1 N ammonium acetate exceeds 100 ppm. Below 75 ppm exchangeable soil K, 186 kg K/ha must be applied for maximum yields. Potassium treatments increased yields at only three of 12 locations studied. Leaf tissue potassium concentration was significantly increased at all locations by the fertilizer treatments. Neutral 1 N ammonium acetate for determining exchangeable K was the best soil analysis extract among those tested for measuring available potassium. Tissue analysis gave no information beyond soil analysis for predicting potassium fertilizer requirements on any soil studied.

The effect of an intrauterine thread on tissue changes in the endometrium of the pseudopregnant rat.

1. Changes in the fresh weight of uterine horns bearing unilateral intrauterine threads have been measured during early pseudopregnancy in the rat.2. Such a thread, which acts as an intrauterine contraceptive device, causes an increase in weight in the horn which carries it, compared to the untreated contralateral horn, on days 2, 4, 5 and 7 of pseudopregnancy. This increase is observed when the device has been present either for 25 or for 45 days.3. The fresh and dry weights of samples of endometrial tissue together with the concentration of chloride and potassium in these samples have also been determined, both in control horns and in horns which have contained a device for 45 days.4. The fresh and dry weights of samples from the device side are greater than the control. However, the weights of the endometrial samples recovered showed considerable variation, particularly in the device side. The weight of water per unit dry weight of endometrial tissue remains constant in the control side but falls steadily from day 2 to day 7 in the device side. The extracellular fluid space, as measured by the weight of chloride per unit dry weight, follows a similar pattern in each side. The weight of potassium per unit dry weight of control tissue falls on days 4 and 5 but rises again on day 7. By contrast, the potassium content of endometrial tissue from the device side falls steadily, reaching its lowest value on day 7.5. These results suggest that the presence of an intrauterine thread alters the composition of the connective tissue matrix of the uterine endometrium. It is likely that these changes are partially responsible for the contraceptive action of such a foreign body.

Biological and technical sources of variability in bovine carcass lean tissue composition. I. Technical variation in measurement of potassium, nitrogen and water.

Biological variation in tissue chemical composition on a fat-free and fat-free dry-matter basis has implication in several fields of biology. This knowledge is particularly important in body composition studies, because many methods of predicting various components of the body are based on the assumption of a constant fat-free body composition. The difficulty of quantifying biological variation, i.e., differences among animals within breed group and treatment, is that measurement errors also afflict each datum. Coefficients of variation in tissue potassium, nitrogen and water concentration, constituents which are of particular interest to body composition workers, usually have not been separated into biological and technical components. Error analysis is an essential part of any study of biological variation. This study examines technical variation in the measurement of potassium, nitrogen and water in the total lean muscle mass of steer carcasses. Seven cuts constituting the entire boneless, trimmed, right side from each of 98 steer carcasses were each sampled once and analyzed in duplicate for ether-extractable materials, N and H2O, within 1 year after samples were collected (Lohman and Norton, 1968), and for K after about 3 years.

Evidence for an electrogenic sodium pump in smooth muscle

Sodium enriched pregnant rat myometrial cell hyperpolarized within two minutes of exposure to potassium containing medium without detectable change in tissue potassium content. The hyperpolarization, which exceeded the potassium equilibrium potential, was temperature- and potassium-dependent and abolished by ouabain. These findings suggest that an electrogenic sodium pump is responsible for the observed hyperpolarization.