Diurnal rhythms in urinary electrolyte excretions by the rat: influence of feeding habits

Cohn, Clarence; Webb, LaVerne; Joseph, Dorothy

doi:10.1016/0024-3205(70)90336-x

Cited by 44 publications

(20 citation statements)

References 16 publications

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“…Other studies have excluded factors such as the adrenals and serum electrolyte concentrations in the gener ation of diurnal electrolyte excretion patterns [3,5]. Food availability cycles may entrain cir cadian rhythms in renal function, partly due to postprandial vasodilation [8]. However, most studies on the influence of food intake and meal size in circadian patterns have either been anecdotal observations or performed in fasting vs. fed state.…”

Section: Discussionmentioning

confidence: 99%

Circadian Variation in Renal Function of the Obese Rat

Luke¹,

Vadiei²

1991

Kidney Blood Press Res

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The influence of food and water intake on renal function was assessed by comparisons between the hyperphagic Zucker obese rat and its lean littermate, which demonstrates nocturnal dominance in activity. Serum creatinine and cortisol levels, creatine kinase activities, creatinine and urine clearances, and sodium and potassium excretion rates were measured over a 24-hour period in both lean and obese rats (n = 24 each). Six rats in each group were studied every 8 h to permit characterization over a 12-hour light/dark cycle at 2-hour intervals. Urine and creatinine clearances were increased in lean rats during the dark phase coincident with onset of eating. Similarly, renal sodium and potassium excretion rates were markedly increased during the dark cycle, despite relatively constant serum potassium and sodium levels over the 24-hour period. In contrast, no circadian patterns in urine and creatinine clearances were found in the obese rat, which exhibits continuous feeding habits throughout the 24-hour period. Moreover, renal electrolyte excretion in the obese rat was modestly increased during the dark cycle, unlike the significant differences over time observed in lean rats. Serum creatinine levels were increased during the dark cycle in both rat groups. Creatine kinase activity, a measure of ambulatory activity, was constant in lean rats during the study period. Although creatine kinase activity was increased in obese rats during the dark cycle, no correlations with renal functional parameters were found. These results indicate that differences in food and water intake are significant determinants in diurnal cyclic changes in renal function.

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Section: Discussionmentioning

confidence: 99%

Circadian Variation in Renal Function of the Obese Rat

Luke¹,

Vadiei²

1991

Kidney Blood Press Res

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“…The urinary excretion of all major solutes (Na ϩ , K ϩ , Cl Ϫ , urea, PO 4 Ϫ , Ca 2ϩ , Mg 2ϩ ) also follows a circadian oscillating pattern. Although, renal excretion rhythms are apparently synchronized with circadian rhythms of activity/feeding, they have been shown to persist over long periods of time under experimental conditions in which external factors such as dietary intake, posture, or sleep were kept constant or were manipulated in a noncircadian manner (10)(11)(12)(13)(14)(15)(16). These results have indicated that in addition to the external circadian stimuli (hormones, food, food metabolites) these functional rhythms are also controlled by a self-sustained intrinsic renal clock.…”

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confidence: 99%

Molecular clock is involved in predictive circadian adjustment of renal function

Zuber

Centeno

Pradervand

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

245

237

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Renal excretion of water and major electrolytes exhibits a significant circadian rhythm. This functional periodicity is believed to result, at least in part, from circadian changes in secretion/reabsorption capacities of the distal nephron and collecting ducts. Here, we studied the molecular mechanisms underlying circadian rhythms in the distal nephron segments, i.e., distal convoluted tubule (DCT) and connecting tubule (CNT) and the cortical collecting duct (CCD). Temporal expression analysis performed on microdissected mouse DCT/CNT or CCD revealed a marked circadian rhythmicity in the expression of a large number of genes crucially involved in various homeostatic functions of the kidney. This analysis also revealed that both DCT/CNT and CCD possess an intrinsic circadian timing system characterized by robust oscillations in the expression of circadian core clock genes (clock, bma11, npas2, per, cry, nr1d1) and clock-controlled Par bZip transcriptional factors dbp, hlf, and tef. The clock knockout mice or mice devoid of dbp/hlf/tef (triple knockout) exhibit significant changes in renal expression of several key regulators of water or sodium balance (vasopressin V2 receptor, aquaporin-2, aquaporin-4, ␣ENaC). Functionally, the loss of clock leads to a complex phenotype characterized by partial diabetes insipidus, dysregulation of sodium excretion rhythms, and a significant decrease in blood pressure. Collectively, this study uncovers a major role of molecular clock in renal function.circadian rhythm ͉ homeostasis ͉ renal function R ecent evidence suggests that many if not all specific physiological functions are under the control of the circadian timing system. The mammalian circadian timing system is a hierarchically organized network of molecular oscillators driven by a central pacemaker located in the suprachiasmatic nucleus (SCN) of hypothalamus. This central pacemaker functions in a self-sustained fashion, but is reset each day by exposure to environmental synchronizers, mainly the light/dark cycle. The SCN masterclock drives the rest-activity cycle, which in turn imposes the feeding pattern [reviewed in (1, 2)]. The feeding time seems to be the dominant cue for circadian rhythms in the peripheral tissues (3, 4). Central and peripheral oscillators share a similar molecular core clock based on a set of self-autonomous transcriptional/ translational feedback loops. The key molecular components of these loops are the PAS domain transcriptional factors CLOCK, BMAL1, and NPAS2 and the feedback repressors PER1, PER2, CRY1, and CRY2. The orphan nuclear receptors NR1D1 and, probably, NR1D2 form an accessory feedback loop. The core oscillators confer circadian rhythmicity on a set of output genes underlying the tissue-specific functional rhythms. Current estimates indicate that up to 10% of the cellular transcriptome may follow a circadian expression pattern (5-7). Several recent studies have also demonstrated that the transcription of only a minority of these circadian genes is driven by systemic humoral or neurona...

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“…Cohn et al, (Cohn C. et al, 1970) have reported that the circadian rhythm of urinary electrolyte excretion in the rat is altered by changing the feeding habits. However, Muratani et al, have reported that there is no change in the circadian rhythm when intravenous hyperalimentation for 24 hours is performed in man, suggesting no influence of food intake.…”

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confidence: 99%

The Possible Role of Endogenous Digitalis-Like Substance in the Regulation of Circadian Changes in Urinary Electrolyte Excretion in Man.

et al. 1989

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The urinary volume (U.V.), Na excretion (UNaV) and K excretion (UKV) have been reported to show a circadian rhythm in man, but the mechanism of this rhythm has not been made clear. To investigate how atrial natriuretic peptide (ANP) and endogenous digitalis-like substance (DLS) participate in the circadian change in urinary electrolyte, the circadian changes in ANP and DLS (digoxin-like immunoactivity: DLI, Na-K-ATPase inhibitor: ATPI, ouabain binding inhibitor to Na-K-ATPase: OBI) were evaluated in 5 normal man. ANP, DLI and OBI showed no significant correlation with urinary electrolyte excretion, but there was a significant positive correlation between plasma ATPI and urinary Na excretion.From these results it is suggested that circulating Na-K-ATPase inhibitor (plasma ATPI) may be involved in the regulation of the circadian rhythm of urinary Na excretion.

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Diurnal rhythms in urinary electrolyte excretions by the rat: influence of feeding habits

Cited by 44 publications

References 16 publications

Circadian Variation in Renal Function of the Obese Rat

Circadian Variation in Renal Function of the Obese Rat

Molecular clock is involved in predictive circadian adjustment of renal function

The Possible Role of Endogenous Digitalis-Like Substance in the Regulation of Circadian Changes in Urinary Electrolyte Excretion in Man.

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