Modifications of circadian cortisol rhythm by cyclic and continuous total enteral nutrition.

Abstract

SummaryTo clarify the relationship between the pattern of diet intake and the circadian adrenocortical rhythm, we measured plasma cortisol levels at 4-h intervals over a 24-h period in 18 patients who were in the vegetative state and had been receiving total enteral nutrition (TEN) for 4 weeks. One group of 6 patients was given a liquid diet intraduodenally and continuously throughout a day (continuous TEN), whereas the two other groups received their daily enteral feeding during a restricted time of day, either in the daytime from 0800h to 2000h (diurnal TEN, 6 patients) or in the nighttime from 2000h to 0800h (nocturnal TEN, 6 patients). In patients with diurnal TEN, there was a clear cortisol rhythm with a peak at 0800h, whose pattern was quite similar to the well-established cortisol rhythm in normal subjects. Patients with nocturnal TEN also showed a cortisol rhythm, but the peak appeared at 1600h. There was no appreciable difference in the amplitude of the rhythm between the two groups. Patients with continuous TEN did not show any consistent circadian cortisol rhythms. Plasma levels of glucose, insulin, and free fatty acids also showed circadian fluctuations corresponding to the pattern of diet infusion in the groups with diurnal and nocturnal TEN, and remained almost constant throughout a day in the group with continuous TEN. We conclude from these results that the timing of diet intake may have a synchronizing effect on the circadian cortisol rhythm in man, as it does in laboratory animals.

Ultradian, circadian and seasonal rhythms in cortisol secretion and adrenal responsiveness to ACTH and yarding in unrestrained red deer (Cervus elaphus) stags

“…The presence of a circadian rhythm in plasma glucocorticoid concentrations is well established in humans (Weitzman et al 1971) and rodents (Keller-Wood & Dallman 1984) and involves an anticipatory rise in cortisol prior to the activity phase, which is typically entrained by circadian rhythms in feeding (Saito et al 1989) and resting (Born et al 1997). In ruminants, contradictory reports exist about the presence of circadian rhythms in basal plasma cortisol concentrations.…”

“…This rhythm is entrained by feeding (Saito et al 1989) and activity/sleep wake cycles (Born et al 1997). There is no evidence from studies of deer for a circadian rhythm in HPA axis activity (white-tailed deer (Odocoileus virginianus) (Bubenik et al 1983); rusa deer (Cervus timorensis) (van Mourik & Stelmasiak 1984); Eld's deer (Monfort et al 1993)).…”

Chronopharmacology of Analgesic Effect and Its Tolerance Induced by Morphine in Mice

“…The 24-h rhythm of physiological and behavioral function, including pain sensitivity, can be shifted by feeding schedule in mice (unpublished data). Also, the timing of diet intake shows a synchronizing effect on the 24-h rhythm of cortisol, body temperature, and urinary excretion in humans (Saito et al, 1989;Nishimura et al, 1992). Feeding schedule may be one of indices to establish the dosing schedule of morphine based on 24-h rhythm of -opioid receptor.…”

Central effects of ghrelin on the adrenal cortex: a morphological and hormonal study

“…Fasting/starvation activates the HPA axis to increase circulating glucocorticoid levels (Dallman et al 1999), whereas constant feeding dampens the normal diurnal peak of the axis (Saito et al 1989). Many neurotransmitters and neuropeptides influence HPA axis activity via actions at hypothalamic and/or suprahypothalamic levels.…”