Diurnal potassium excretory cycles in the rat

1986 ◽  
Vol 250 (5) ◽  
pp. F930-F941 ◽  
Author(s):  
L. Rabinowitz ◽  
C. J. Wydner ◽  
K. M. Smith ◽  
H. Yamauchi
Keyword(s):  
Extracellular Fluid ◽  
Potassium Content ◽  
Extracellular Potassium ◽  
Dark Phase ◽  
Adrenal Steroids ◽  
Light Phase ◽  
High Potassium ◽  
Potassium Intake ◽  
Low Levels ◽  
Adrenalectomized Rats

Diurnal potassium cycles (DPC) were measured in unanesthetized undisturbed rats fed a liquid diet and maintained in a 12-h light-dark environment. A fourfold step increase in diet potassium content increased DPC amplitude without altering phase. After presentation of the high-potassium diet, the initial adaptive increase in excretion occurred within 1.5 h (diet given during dark phase) and within 6 h (diet given during light phase). On a day when food was withheld (no potassium intake), DPC were present but with a lowered amplitude. The amount of potassium excreted on a fasting day exceeded gut and extracellular fluid potassium content and was only modestly increased when rats were previously fed a high-potassium diet. In adrenalectomized rats that received no steroid replacement or received constant infusions of low levels of aldosterone, dexamethasone, or aldosterone plus dexamethasone, potassium balance and DPC were normal. It is concluded that the amplitude of DPC in the rat is determined in part by the availability of potassium from both intracellular and extracellular potassium pools; mechanisms independent of potassium intake can generate the DPC; and the presence or the cyclic secretion of adrenal steroids is not necessary for the generation of DPC in the rat.

Kaliuretic regulatory factors in the rat

1987 ◽  
Vol 253 (6) ◽  
pp. F1182-F1196 ◽  
Author(s):  
J. C. Rutledge ◽  
L. Rabinowitz
Keyword(s):  
Sodium Intake ◽  
Plasma Potassium ◽  
Urine Excretion ◽  
High Potassium ◽  
Regulatory Factors ◽  
Potassium Intake ◽  
Excretion Rates ◽  
Caloric Balance ◽  
Adrenalectomized Rats

To evaluate the role of aldosterone, plasma potassium, and sodium and urine excretion rates in controlling both total daily potassium excretion and the diurnal cyclic excretion of potassium, we performed experiments on unanesthetized, undisturbed rats kept in a 12-h light/12-h dark environment and fed a liquid diet. Independent variations were imposed on potassium intake, sodium intake, and, in groups of adrenalectomized rats, on aldosterone infusion rates. Potassium intake was 2.6, 10.6, and 18.7 meq/day. Sodium intake was 2.1, 6.7, and 17 meq/day. Aldosterone infusion was 0.1, 0.4, 1, and 10 times a basal rate of 1 microgram.day-1.100 g-1, with constant dexamethasone infusion at 1.43 micrograms.day-1.100 g-1. Twenty-four-hour excretion of potassium and sodium balanced 24-h intake of potassium and sodium regardless of the imposed combination of known regulatory factors. The amplitudes of potassium and sodium excretion during the diurnal cycle were each closely related to the ongoing levels of potassium and sodium intake. Plasma potassium was measured at the peak of the potassium cycle. It is suggested, based on analysis of the results, that when caloric balance was maintained, the amplitude of the diurnal potassium cycle was not importantly influenced by the rates of sodium and urine excretion, and, in addition to effects of aldosterone and plasma potassium concentration, the amplitude was importantly influenced by unspecified, homeostatically effective kaliuretic factors. Adrenalectomized rats receiving subbasal aldosterone replacement rejected the high potassium diet, were anuric, lost weight, and were severely hyperkalemic, observations indicating the necessity of adequate aldosterone for maintenance of potassium homeostasis.

Antagonism of Depressed Extracellular Potassium Levels Against Histamine Toxicity in Mice

1957 ◽  
Vol 191 (3) ◽  
pp. 583-586 ◽  
Author(s):  
William H. Macmillan
Keyword(s):  
Protective Action ◽  
Plasma Potassium ◽  
Normal Diet ◽  
Potassium Content ◽  
Extracellular Potassium ◽  
Confidence Limits ◽  
Total Body Potassium ◽  
High Potassium ◽  
Low Potassium ◽  
Total Body

The lethality of histamine was studied in three groups of 110 CFw mice fed low, normal and high potassium content diets, respectively, for 5 weeks. The plasma potassium levels of the three groups on the 34th day were 3.2 ± 0.4 mEq K+/l. for the mice on the low potassium content, 5.7 ± 0.8 mEq K+/l. for the group on normal diet, and 5.4 ± 0.4 mEq K+/l. for the group on high potassium diet. The ld50's and 19/20 confidence limits for the respective groups to intravenous histamine were 240 (220.2–261.6) mg/kg, 189 (170.3–209.8) mg/kg, and 155 (142.5–168.6) mg/kg. These data indicate that a reduction in total body potassium offers a protective action against the production of histamine death in mice and confirm earlier reports that the presence of potassium in this species enhances the toxic effects of histamine. The results obtained cannot be explained on the basis of delayed circulation time, renal or adrenal pathology; however, they suggest a possible mechanism to explain the protective action of fasting against histamine toxicity in this species.

Studies on the Hypotensive Effect of High Potassium Intake in Patients with Essential Hypertension

1981 ◽  
Vol 61 (s7) ◽  
pp. 77s-80s ◽  
Author(s):  
Osamu Iimura ◽  
Toshiaki Kijima ◽  
Kenjiro Kikuchi ◽  
Akiyoshi Miyama ◽  
Toshiaki Ando ◽  
...  
Keyword(s):  
Essential Hypertension ◽  
Control Period ◽  
Extracellular Fluid ◽  
Hypotensive Effect ◽  
Fluid Volume ◽  
Electrolyte Balance ◽  
High Potassium ◽  
Plasma Aldosterone Concentration ◽  
Potassium Intake ◽  
Potassium Loading

1. In order to confirm and investigate the hypotensive effect of a high potassium intake we compared mean arterial pressure (MAP), water and electrolyte balance, plasma and urinary noradrenaline (NA), plasma renin activity (PRA) and plasma aldosterone concentration (PAC) in 20 inpatients with mild or moderate essential hypertension on a control diet (Na: 260, K: 75 mmol/day), and after high (K: 175 mmol/day) and low potassium diets (K: 25 mmol/day). 2. After potassium loading, urinary volume (UV) and urinary excretion of sodium (UNaV) and of potassium (UKV) were elevated, and MAP, body weight, plasma volume (PV), extracellular fluid volume (ECFV) and total exchangeable sodium (Nae) were reduced significantly. 3. After potassium loading, PRA, PAC, plasma and urinary NA increased and the pressor response to infused noradrenaline and angiotensin II decreased significantly. 4. The reduction of MAP after potassium loading correlated positively with PV and ECFV during the control period. In addition, significant correlations were found between ΔUV and ΔUNaV, —ΔPV and ΔU/NaV, —ΔPV and Δ plasma NA, and Δ plasma NA and Δ PRA. 5. Patients with low PRA had high PV, ECFV and Nae during the control period, and showed greater reductions of MAP, PV, ECFV and Nae after potassium loading. 6. After potassium restriction, UNaV, PRA and urinary NA decreased and PV increased, and MAP did not change significantly. 7. These results suggest that the hypotensive effect of high potassium intake may be caused by reduction of body fluid volume via augmentation of Na excretion.

scholarly journals PENGARUH PENAMBAHAN EKSTRAK DAUN ALPUKAT (Persea americana, mill) TERHADAP MUTU ORGANOLEPTIK DAN KADAR KALIUM PUDING PISANG

2018 ◽  
Vol 9 (2) ◽  
pp. 58
Author(s):  
Putri Aulia Arza ◽  
Suci Purnama Sari
Keyword(s):  
Leaf Extract ◽  
Design Method ◽  
Persea Americana ◽  
Potassium Content ◽  
High Potassium ◽  
Organoleptic Quality ◽  
Randomized Design ◽  
Low Levels ◽  
Completely Randomized Design ◽  
High Potassium Content

Leaf avocado (Persea americana, mill) and Banana Mas (Moses sp) is a plant that has high potassium content and low levels of sodium. The purpose of this research is to analyze the effect of addition of avocado leaf extract to organoleptic quality and potassium banana pudding level. Type of research is true experimental with completely randomized design method. The data used was obtained directly from 25 semi trained panelists. Data analyzed by using ANOVA, if different real continued with Test Duncan. Addition of Leaf avocado and Banana Mas affect the levels of acceptance in terms of color, aroma and flavor but does not affect the texture. Addition of eggs also affects the level of potassium. Best assessment results obtained on treated banana with the addition of avocado leaf extract as much 250 ml ©. Potassium content of pudding with adding leaf avocado 0, 200ml dan 250ml respectively 0,0365 %, 0,0577 %, 0,0790 %

Changes in body temperature of rats acclimated to heat with different acclimation schedules

1989 ◽  
Vol 67 (5) ◽  
pp. 2154-2157 ◽  
Author(s):  
O. Shido ◽  
Y. Yoneda ◽  
T. Nagasaka
Keyword(s):  
Wistar Rats ◽  
Heat Exposure ◽  
Heat Acclimation ◽  
Dark Phase ◽  
Light Phase ◽  
Dark Cycle ◽  
Hypothalamic Temperature ◽  
Male Wistar Rats ◽  
The Mean ◽  
Low Levels

Male Wistar rats, initially maintained at an ambient temperature (Ta) of 23.8 degrees C, were subjected to one of seven different heat acclimation schedules under a 12:12-h light-dark cycle (lights on at 0600 h). Two groups of rats were exposed to Ta of 32.4 degrees C all day for 5 (HC5) or 10 (HC10) days. The other four groups were exposed to Ta of 32.8 degrees C for 5 h/day during the last half of the dark phase for 5 (NI5) or 10 (NI10) consecutive days or during the last half of the light phase for 5 (DI5) or 10 (DI10) consecutive days. Control rats (C) were kept at 23.8 degrees C throughout the experiment. Hypothalamic temperature (Thy) was measured every 5 min with a chronically implanted thermocouple from 1 day before the beginning to 2 days after the end of the heat acclimation periods. During the heat acclimation periods, daily mean Thy rose significantly in HC5 and HC10 rats but decreased significantly in NI5 and NI10 rats. Daily mean Thy did not change in C, DI5, and DI10 rats. Thy in HC10 rats sharply decreased at the end of the heat acclimation periods and remained at low levels for approximately 3 h. On the 2nd postacclimation day, however, mean Thy returned and remained at a significantly higher level. In NI10 rats, the mean Thy in the postacclimation period was significantly lower than the preacclimation values. No such changes in mean Thy were observed in DI10 rats. Five-days of heat exposure had little effect on the postacclimation Thy.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Diurnal Rhythm of Apolipoprotein A-IV in Rat Hypothalamus and Its Relation to Food Intake and Corticosterone

Endocrinology ◽  
2004 ◽  
Vol 145 (7) ◽  
pp. 3232-3238 ◽  
Author(s):  
Min Liu ◽  
Ling Shen ◽  
Yin Liu ◽  
Daisuke Tajima ◽  
Randall Sakai ◽  
...  
Keyword(s):  
Food Intake ◽  
Dark Phase ◽  
Light Phase ◽  
Daily Food Intake ◽  
Protein Levels ◽  
Diurnal Patterns ◽  
Apolipoprotein A ◽  
Daily Food ◽  
Gene And Protein Expression ◽  
Low Levels

Abstract Apolipoprotein A-IV (apo A-IV) is a satiety protein synthesized in the small intestine and hypothalamus. To further understand the roles of central apo A-IV in the management of daily food intake, we have examined the diurnal patterns of hypothalamic apo A-IV gene and protein expression in freely feeding and food-restricted (food provided 4 h daily between 1000 h and 1400 h) rats. In freely feeding rats, the hypothalamic apo A-IV mRNA and protein levels fluctuated, with high levels during the light phase, peaking at 0900 h (3 h after lights on), and low levels during the dark phase, with a nadir at 2100 h (3 h after lights off). The daily patterns of the fluctuation, however, were altered in food-restricted rats, which had a marked decrease in hypothalamic apo A-IV mRNA and protein levels during the 4 h-feeding period of the light phase. Although corticosterone (CORT) secretion temporally coincided with the decreasing phase of apo A-IV in the hypothalamus, depletion of CORT by adrenalectomy significantly decreased, rather than increased, hypothalamic apo A-IV mRNA and protein levels. These results indicate that the diurnal expression of hypothalamic apo A-IV is regulated by factors other than the circulating CORT, for example, the reduced food intake and body weight in adrenalectomized animals. The fact that hypothalamic apo A-IV level and food intake were inversely related during the normal diurnal cycle as well as in the period of restricted feeding suggests that hypothalamic apo A-IV is involved in the regulation of daily food intake.

Effect of Adrenalectomy on Production and Excretion of Ammonia by the Kidneys

1957 ◽  
Vol 188 (3) ◽  
pp. 524-528 ◽  
Author(s):  
Jean D. Wilson ◽  
Donald W. Seldin
Keyword(s):  
Sodium Chloride ◽  
Enzyme System ◽  
Ammonia Excretion ◽  
Tubular Reabsorption ◽  
Adrenal Steroids ◽  
Potassium Intake ◽  
Exchange Site ◽  
Circulatory Insufficiency ◽  
Salt Depletion ◽  
Adrenalectomized Rats

The rate and magnitude of ammonia excretion and renal glutaminase adaptation is normal in adrenalectomized rats given moderate (up to 4 mEq/day) amounts of NH4Cl. The administration of large amounts of NH4Cl (5 mEq/day or more) invariably kills adrenalectomized rats. Shortly before death, renal glutaminase adaptation was normal. Survival of adrenalectomized rats on large amounts of NH4Cl could be prolonged if potassium was eliminated from the diet. Notwithstanding the prevention of hyperkalemia by restricting potassium intake and salt depletion by the provision of adequate amounts of sodium chloride, ammonia excretion is impaired in rats given large doses of NH4Cl despite normal adaptation of renal glutaminase. It is suggested that adrenal steroids are not involved in either the maintenance or activation of the glutaminase enzyme system in the kidneys of rats. In adrenalectomized rats given large doses of NH4Cl, the diminished excretion of ammonia appears to be a consequence of a diminished Na+–H+ exchange resulting from two disturbances: a) reduced delivery of Na+ to distal tubular exchange site, owing to peripheral circulatory insufficiency arising from salt depletion or potassium intoxication; b) a specific impairment of tubular reabsorption of Na+ owing to the absence of adrenal steroids.

scholarly journals Melatonin MT1 and MT2 Receptors Exhibit Distinct Effects in the Modulation of Body Temperature across the Light/Dark Cycle

2019 ◽  
Vol 20 (10) ◽  
pp. 2452 ◽  
Author(s):  
Martha López-Canul ◽  
Seung Hyun Min ◽  
Luca Posa ◽  
Danilo De Gregorio ◽  
Annalida Bedini ◽  
...  
Keyword(s):  
Body Temperature ◽  
Receptor Antagonist ◽  
Partial Agonist ◽  
Receptor Subtypes ◽  
Dark Phase ◽  
Light Phase ◽  
Dark Cycle ◽  
Simultaneous Activation ◽  
Type 3 ◽  
G Protein Coupled

Melatonin (MLT) is a neurohormone that regulates many physiological functions including sleep, pain, thermoregulation, and circadian rhythms. MLT acts mainly through two G-protein-coupled receptors named MT1 and MT2, but also through an MLT type-3 receptor (MT3). However, the role of MLT receptor subtypes in thermoregulation is still unknown. We have thus investigated the effects of selective and non-selective MLT receptor agonists/antagonists on body temperature (Tb) in rats across the 12/12-h light–dark cycle. Rectal temperature was measured every 15 min from 4:00 a.m. to 9:30 a.m. and from 4:00 p.m. to 9:30 p.m., following subcutaneous injection of each compound at either 5:00 a.m. or 5:00 p.m. MLT (40 mg/kg) had no effect when injected at 5 a.m., whereas it decreased Tb during the light phase only when injected at 5:00 p.m. This effect was blocked by the selective MT2 receptor antagonist 4P-PDOT and the non-selective MT1/MT2 receptor antagonist, luzindole, but not by the α1/MT3 receptors antagonist prazosin. However, unlike MLT, neither the selective MT1 receptor partial agonist UCM871 (14 mg/kg) nor the selective MT2 partial agonist UCM924 (40 mg/kg) altered Tb during the light phase. In contrast, UCM871 injected at 5:00 p.m. increased Tb at the beginning of the dark phase, whereas UCM924 injected at 5:00 a.m. decreased Tb at the end of the dark phase. These effects were blocked by luzindole and 4P-PDOT, respectively. The MT3 receptor agonist GR135531 (10 mg/kg) did not affect Tb. These data suggest that the simultaneous activation of both MT1 and MT2 receptors is necessary to regulate Tb during the light phase, whereas in a complex but yet unknown manner, they regulate Tb differently during the dark phase. Overall, MT1 and MT2 receptors display complementary but also distinct roles in modulating circadian fluctuations of Tb.

48 High Potassium Intake Lowers Blood Pressure in Essential Hypertension

1984 ◽  
Vol 2 (1) ◽  
pp. 114 ◽  
Author(s):  
A Overlack ◽  
K O Stumpe ◽  
H M M??ller ◽  
R Kolloch ◽  
F Kr??ck
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
High Potassium ◽  
Potassium Intake

Locomotor activity responses in juvenile sockeye salmon, Oncorhynchus nerka, to melatonin and serotonin

1970 ◽  
Vol 48 (6) ◽  
pp. 1425-1427 ◽  
Author(s):  
John E. Byrne
Keyword(s):  
Locomotor Activity ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Dark Phase ◽  
Light Phase ◽  
Selective Activity

Intraperitoneal injections administered for 3 consecutive days to juvenile sockeye salmon resulted in selective activity responses to either the light or the dark phase of the photoperiodic cycle. Serotonin increased locomotor activity only during the dark phase, while melatonin decreased locomotor activity only during the light phase.

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