Circadian rhythm in blood glucose levels in normal and hepatectomized mice

Llanos, J. M. Echave; Vaccaro, Mario

doi:10.1080/09291017209359294

Cited by 7 publications

(7 citation statements)

References 8 publications

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“…Variations in blood glucose levels in control mice sampled at various times of the day are due to the normal circadian rhythm, observed even in fasting animals (22,27). The pronounced depression of blood glucose (to as low as 4 mg/dl in some animals; group mean = 31 mg/dl) which occurred in endotoxin-treated adrenalectomized mice at 6 h was significantly greater than that seen in intact animals (60 mg/dl).…”

Section: Discussionmentioning

confidence: 99%

Influence of endotoxin treatment on dexamethasone induction of hepatic phosphoenolpyruvate carboxykinase

McCallum¹,

Seale²,

Stith³

1983

Infect Immun

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Decreased glucocorticoid binding has been observed at a time after endotoxin (3 to 6 h) when imparied liver enzyme induction is known to occur. This study was undertaken to characterize the early time course of hypoglycemia and decreased liver phosphoenolpyruvate carboxykinase (PEPCK) activity in intact and adrenalectomized mice given endotoxin. In addition, altered steroid induction of hepatic PEPCK was examined in adrenalectomized mice given dexamethasone at intervals before and after a median lethal dose of endotoxin. Intact mice demonstrated a dramatic hyperglycemia at 1 h after endotoxin treatment, a response absent in adrenalectomized mice. Plasma glucose levels were significantly reduced from control values at 3 and 6 h posttreatment, with the most pronounced endotoxin-induced hypoglycemia seen in adrenalectomized mice. Hepatic PEPCK activity in intact mice given endotoxin was decreased at 3 and 6 h after treatment, although no change from basal, noninduced levels was seen in poisoned adrenalectomized mice. The increased increment in hepatic PEPCK activity due to fasting of intact control mice was reproduced in adrenalectomized control mice by the administration of dexamethasone. Furthermore, the induction of hepatic PEPCK by dexamethasone was inhibited by 1 h after endotoxin treatment, with enzyme activity falling to basal, noninduced levels by 6 h posttreatment. At these same time intervals after endotoxin treatment, no evidence of histopathology in the liver or adrenal glands was seen. These results coincide with changes in steroid binding seen previously and indicate that endotoxin treatment produces significant alterations in glucocorticoid action at the subcellular or molecular level.

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Section: Discussionmentioning

confidence: 99%

Influence of endotoxin treatment on dexamethasone induction of hepatic phosphoenolpyruvate carboxykinase

McCallum¹,

Seale²,

Stith³

1983

Infect Immun

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“…As temperature entrains circadian rhythms in in vitro populations of the blood-dwelling unicellular parasite, Trypanosoma brucei [7], it may be an important cyclical cue for S. mansoni as well. Other environmental stressors known to activate the heat shock pathway include hypoxia and reactive oxygen species [71] and as mouse blood oxygen and glucose levels increase during the dark phase [18,19], they could also induce the transcription of heat shock proteins in mansoni. Circumstantial evidence points towards the nocturnal peaks in the expression of heat shock and related genes being involved in proteotoxic stress rather than a period of protein synthesis, because it is synchronous with the mouse's active phase (and accompanying increases in environmental stressors) and in anti-phase (at the opposite time of day) to rhythmic processes involved in translation regulation and protein synthesis (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…6 Schematic summarising daily rhythms in the transcriptomes of adult Schistosoma mansoni and the mouse vasculature. Rhythms in the transcriptomes of S. mansoni identified from diel gene functional enrichment analyses and rhythms in the mouse vasculature summarised from the literature ( i [21], ii [15], iii [16], iv [78], v [17], vi [18], vii [19], viii [81]). Side plot showing temporal expression profile of Smk1-1(Smp_307450), the diel gene with the highest amplitude in male worms and a proposed vaccine candidate.…”

Section: Day-time Peaking Genes (Host Resting Phase)mentioning

confidence: 99%

“…The mouse, M. musculus, is also the model species routinely used to study circadian rhythms in mammals [14], and because of this, we know there are many daily rhythmic fluctuations in the vasculature (e.g. temperature, pressure, oxygen, glucose, red and white blood cells [15][16][17][18][19]) that may act as zeitgebers (German for "time giver" or synchroniser) to influence the worm's biology and potentially its rhythms.…”

Section: Introductionmentioning

confidence: 99%

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Daily rhythms in gene expression of the human parasite Schistosoma mansoni

Rawlinson

Reid

et al. 2021

BMC Biol

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Background The consequences of the earth’s daily rotation have led to 24-h biological rhythms in most organisms. Even some parasites are known to have daily rhythms, which, when in synchrony with host rhythms, can optimise their fitness. Understanding these rhythms may enable the development of control strategies that take advantage of rhythmic vulnerabilities. Recent work on protozoan parasites has revealed 24-h rhythms in gene expression, drug sensitivity and the presence of an intrinsic circadian clock; however, similar studies on metazoan parasites are lacking. To address this, we investigated if a metazoan parasite has daily molecular oscillations, whether they reveal how these longer-lived organisms can survive host daily cycles over a lifespan of many years and if animal circadian clock genes are present and rhythmic. We addressed these questions using the human blood fluke Schistosoma mansoni that lives in the vasculature for decades and causes the tropical disease schistosomiasis. Results Using round-the-clock transcriptomics of male and female adult worms collected from experimentally infected mice, we discovered that ~ 2% of its genes followed a daily pattern of expression. Rhythmic processes included a stress response during the host’s active phase and a ‘peak in metabolic activity’ during the host’s resting phase. Transcriptional profiles in the female reproductive system were mirrored by daily patterns in egg laying (eggs are the main drivers of the host pathology). Genes cycling with the highest amplitudes include predicted drug targets and a vaccine candidate. These 24-h rhythms may be driven by host rhythms and/or generated by a circadian clock; however, orthologs of core clock genes are missing and secondary clock genes show no 24-h rhythmicity. Conclusions There are daily rhythms in the transcriptomes of adult S. mansoni, but they appear less pronounced than in other organisms. The rhythms reveal temporally compartmentalised internal processes and host interactions relevant to within-host survival and between-host transmission. Our findings suggest that if these daily rhythms are generated by an intrinsic circadian clock then the oscillatory mechanism must be distinct from that in other animals. We have shown which transcripts oscillate at this temporal scale and this will benefit the development and delivery of treatments against schistosomiasis.

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“…This phenomenon may have evolved to optimize host encounters and increase transmission. 78,79 Recent transcriptomic analysis has revealed rhythmic gene expression in adult S. mansoni parasites residing within the mesenteric vasculature of rodent hosts, an environment exposed to daily changes in temperature, 80 pressure, 81 oxygen levels, 82 glucose levels 83 and leukocytes 2 which may all contribute rhythmic signals to influence parasite function. 84 Indeed, approximately 2% of S. mansoni genes exhibited time-of-day dependent expression, including genes involved in stress response peaking during the night and genes involved in metabolic activity peaking during the day, correlating with the host's active and resting phase respectively.…”

Section: How Par a S Ite S Tell Timementioning

confidence: 99%

Circadian rhythms in immunity and host‐parasite interactions

Hunter

Butler

Gibbs

2022

Parasite Immunology

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The mammalian immune system adheres to a 24 h circadian schedule, exhibiting daily rhythmic patterns in homeostatic immune processes, such as immune cell trafficking, as well as the inflammatory response to infection. These diurnal rhythms are driven by endogenous molecular clocks within immune cells which are hierarchically coordinated by a light‐entrained central clock in the suprachiasmatic nucleus of the hypothalamus and responsive to local rhythmic cues including temperature, hormones and feeding time. Circadian control of immunity may enable animals to anticipate daily pathogenic threat from parasites and gate the magnitude of the immune response, potentially enhancing fitness. However, parasites also strive for optimum fitness and some may have co‐evolved to benefit from host circadian timing mechanisms, possibly via the parasites’ own intrinsic molecular clocks. In this review, we summarize the current knowledge surrounding the influence of the circadian clock on the mammalian immune system and the host‐parasitic interaction. We also discuss the potential for chronotherapeutic strategies in the treatment of parasitic diseases.

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Circadian rhythm in blood glucose levels in normal and hepatectomized mice

Cited by 7 publications

References 8 publications

Influence of endotoxin treatment on dexamethasone induction of hepatic phosphoenolpyruvate carboxykinase

Influence of endotoxin treatment on dexamethasone induction of hepatic phosphoenolpyruvate carboxykinase

Daily rhythms in gene expression of the human parasite Schistosoma mansoni

Circadian rhythms in immunity and host‐parasite interactions

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