Diurnal variation of liver glycogen and plasma free fatty acids in rats fed ad libitum or single daily meal

Fuller, Ray W.; Diller, E. R.

doi:10.1016/0026-0495(70)90056-9

Cited by 113 publications

(36 citation statements)

References 11 publications

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“…Others have also reported diurnal changes in hormones and fuels that do not appear to be related merely to meals (25)(26)(27). The insulin responses during the continual feeding were significantly lower after an evening than after a morning meal.…”

Section: Discussionmentioning

confidence: 93%

Diurnal fluctuations in triglyceride, free fatty acids, and insulin during sucrose consumption and insulin infusion in man

Barter¹,

Carroll²,

Nestel³

1971

J. Clin. Invest.

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A B S T R A C T Serial changes in circulating triglyceride, free fatty acids (FFA), insulin, and glucose have been measured in human subjects fed sucrose as the sole source of calories for 2-or 3-day periods. The sucrose was given either during the day with overnight fasting (19 subjects) or as continual 3-hour meals during the day and night (seven subjects). Insulin was infused overnight in five additional subjects on the day-feeding regimen to determine the effect on triglyceride concentration.The concentration of triglyceride increased during the study in all subjects, but there was a clear diurnal pattern in the response which was present even in the continual feeding studies. The rise in triglyceride occurred mainly overnight, and during the day there was frequently a fall in the concentration. The overnight increase was significantly less when insulin was infused. There were also diurnal fluctuations in FFA and insulin in both daytime and continual feeding regimens. The plasma FFA, like triglyceride, rose during the night and fell during the day while the insulin rose during the day and fell overnight.Separate statistical analysis of the daytime and overnight changes revealed that the changes in triglyceride were significantly but negatively correlated with changes in insulin during both periods. The changes in triglyceride and FFA were positively correlated during the day but not significantly related during the night. The data show that when sucrose is eaten for 2 or 3 days, there is a general increase in triglyceride concentration upon which are superimposed major diurnal fluctuations in the concentrations of triglyceride, insulin, and FFA. It is suggested that the highly significant inverse relationship between changes in triglyceride and insulin may be mediated through an effect of insulin on triglyceride removal.

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Section: Discussionmentioning

confidence: 93%

Diurnal fluctuations in triglyceride, free fatty acids, and insulin during sucrose consumption and insulin infusion in man

Barter¹,

Carroll²,

Nestel³

1971

J. Clin. Invest.

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“…These include sympathetic activity, circulating insulin, thyroid hormone, and corticosteroid levels, as well as circulating fuels such as glucose, fatty acids, and ketone bodies. [22][23][24][25][26] All of these factors have the potential to affect cardiac function, metabolism, and gene expression to varying degrees. For example, thyroid hormone can affect the expression of various metabolic genes, including glut4, ucp2, ucp3, as well as contractile proteins.…”

Section: Potential Mechanisms Of Cardiac Circadian Rhythmsmentioning

confidence: 99%

Intrinsic Diurnal Variations in Cardiac Metabolism and Contractile Function

Young

Razeghi

Cedars

et al. 2001

Circulation Research

184

162

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Abstract-Diurnal variation of cardiac function in vivo has been attributed primarily to changes in factors such as sympathetic activity. No study has investigated previously the intrinsic properties of the heart throughout the day. We therefore investigated diurnal variations in metabolic flux and contractile function of the isolated working rat heart and how this related to circadian expression of metabolic genes. Contractile performance, carbohydrate oxidation, and oxygen consumption were greatest in the middle of the night, with little variation in fatty acid oxidation. The expression of all metabolic genes investigated (including regulators of carbohydrate utilization, fatty acid oxidation, and mitochondrial function) showed diurnal variation, with a general peak in the night. In contrast, pressure overloadinduced cardiac hypertrophy completely abolished this diurnal variation of metabolic gene expression. Thus, over the course of the day, the normal heart anticipates, responds, and adapts to physiological alterations within its environment, a trait that is lost by the hypertrophied heart. We speculate that loss of plasticity of the hypertrophied heart may play a role in the subsequent development of contractile dysfunction. Key Words: function Ⅲ gene expression Ⅲ metabolism Ⅲ perfusions Ⅲ rat C ells are able to anticipate, respond, and adapt to fluctuations in their environment. Anticipation is achieved through self-sustained intracellular clocks, providing advantageous priming of the cell in preparation to a given stimulus. 1 The response of any cell is dictated by the level of the stimulus, as well as the sensitivity to that stimulus. The latter is affected by both intracellular (genotype, circadian clocks) and extracellular (eg, neuronal and humoral factors) influences. The resultant adaptation can be either immediate (alterations in preexisting proteins) or prolonged (changes in gene and protein expression) depending on the length of exposure to the stimulus.The heart, not unlike other organs, possesses both internal clocks and the ability to respond to external stimuli, both of which could potentially influence gene expression, metabolism, and function. [2][3][4] It is well known that the onset of heart failure, myocardial infarction, and sudden death is greatest in the early hours of the morning. 5-7 For this reason, several studies have investigated diurnal variation in cardiac function in vivo, in both rodents and humans, and have correlated findings with fluctuations in neurohumoral influences. 5,8 -11 However, to date, no study has either postulated or investigated whether the intrinsic properties of the heart fluctuate during the day, or whether loss of synchronization between the presence of a stimulus (eg, sympathetic activity) and responsiveness of the heart plays a role in the development of contractile dysfunction.We set out to characterize the diurnal variation in contractile function and metabolic flux of the heart in the absence of confounding extracardiac influences by using the isolat...

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“…Schedules of restricted daily meals can substantially modulate the distribution of an animal's behavioural and metabolic activities (Fuller & Diller, 1970;Krieger, 1974;Moberg, Bellinger & Mendel, 1975). When food access is limited to a few hours at a fixed time once a day, for instance, a great increase of locomotion is found during the hours before meal time (Bolles & Stokes, 1965;Boulos, Rosenwasser & Terman, 1980;.…”

Section: Introductionmentioning

confidence: 99%

Effect of heat acclimation on diurnal changes in body temperature and locomotor activity in rats.

Shido

Sakurada

Nagasaka

1991

The Journal of Physiology

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SUMMARY1. The present study was performed to examine the effects of heat exposure for hours at a fixed time once a day on diurnal variations of deep body temperature, heat balance and locomotor activity in rats.2. The heat-exposed group (HE) was subjected to an ambient temperature of 33-5°C for about 5 h in the last half of the dark phase daily for at least 10 consecutive days, while the control rats were constantly kept at 24 'C.3. After the completion of the heat exposure schedule, hypothalamic temperature (Thy), heat loss, heat production and locomotor activity of HE rats significantly decreased for 3-4 h during the period of previous heat exposure time and formed a characteristic trough in the dark phase, which was never observed in the control rats or in the HE rats before the start of the heat exposure schedule.4. The troughs of Thy, heat loss and heat production in the dark phase were persistent for at least 2 days after the end of the heat exposure schedule. The reductions of locomotor activity in this period were, however, observed only on the first day after stopping the heat exposure schedule. 5. These results suggest that the time memory for heat exposure was formed in heat-acclimated rats and was persistent for at least 2 days after the removal of heat exposure. It is also concluded that the reduction in metabolic heat production contributed to the fall of Thy during the period of heat exposure.

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Diurnal variation of liver glycogen and plasma free fatty acids in rats fed ad libitum or single daily meal

Cited by 113 publications

References 11 publications

Diurnal fluctuations in triglyceride, free fatty acids, and insulin during sucrose consumption and insulin infusion in man

Diurnal fluctuations in triglyceride, free fatty acids, and insulin during sucrose consumption and insulin infusion in man

Intrinsic Diurnal Variations in Cardiac Metabolism and Contractile Function

Effect of heat acclimation on diurnal changes in body temperature and locomotor activity in rats.

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