Pattern of Plasma Cortisol during the 24-Hour Sleep/Wake Cycle in the Rhesus Monkey*

Abstract

The 24-h pattern of plasma cortisol and changes induced by alterations of the sleep/wake cycle were studied in 12 male rhesus monkeys. The chair-living animals were chronically prepared with a right atrial catheter and electroencephalogram electrodes. Hormone (blood samples every 15 min) and continuous activity/electroencephalogram profiles were obtained from the adjacent room for 96 h (4 animals), 24 h or various shorter periods of time. Plasma cortisol showed a circadian rhythm with a late evening minimum (1900-2100 h; approximately 60 micrograms/liter) and an early morning maximum (0400-0700 h; approximately 160 micrograms/liter). Superimposed were episodic fluctuations for which powerspectral analysis showed a weakly expressed 30- to 60-min periodicity in 24 of 27 24-h profiles. Cross-correlation analysis indicated no relation between cortisol on the one hand and daytime activity-arousal, nocturnal waking, slow wave sleep (SWS) or rapid eye movement sleep (REM), respectively. Five-hour total sleep deprivation, specific SWS-deprivation, and severe disruption of the REM-pattern provided no evidence for an immediate effect of sleep onset or sleep stages on the cortisol pattern. Cortisol rose significantly after termination of the 5-h deprivation, but the mechanism of this elevation remains to be determined. Cross-correlation analysis between the cortisol time series and those of GH, PRL, and TSH from already published data gave no evidence for a regular temporal relationship between the episodic patterns of these hormones.

Dihydrotestosterone differentially modulates the cortisol response of the hypothalamic–pituitary–adrenal axis in male and female rhesus macaques, and restores circadian secretion of cortisol in females

“…A separate analysis examining the effect of DHT doses compared individually to placebo on basal CORT in DOM female monkeys found that there was also a significant treatment by time effect on diurnal cortisol comparing the low-dose DHT with placebo (F (1, 3)=250.845, p=0.001) indicating a reversal in levels from 9 a.m. to 9 p.m. and a restoration of normal CORT circadian rhythm (see:(Plant, 1981; Quabbe et al, 1982) with low DHT treatment. High-dose DHT also restored circadian rhythm (F (1, 3)=95.531, p=0.002) and significantly lowered basal CORT (F (1, 3)=115.927, p=0.002).…”

Clock Genes and Clock-Controlled Genes in the Regulation of Metabolic Rhythms

“…Cortisol and melatonin secretions span two opposing halves of the day in diurnal animals, so that the SCN may influence peripheral oscillators with two different hormones acting in a time-qualified manner. In diurnal mammals and humans, cortisol secretion begins in the middle of the night and reaches its zenith in the early morning near awakening, whereas melatonin secretion begins in the late evening and reaches its zenith early in the sleep-span (Mazzoccoli et al, 2011;Quabbe et al, 1982). On the contrary, in nocturnal animals, cortisol and melatonin are secreted during the same phase with respect to the light/dark cycle, as daily variations in plasma corticosteroid display maximal values at dusk (Atkinson & Waddell, 1997).…”

Evidence for episodic but not circadian activity in plasma concentrations of adrenocorticotrophin, cortisol and thyroxine in dogs

“…Plasma levels of adrenocorticotrophin (ACTH), corticosteroids or both have been shown to vary episodically and with circadian periodicity in several species including man (Krieger, Allen, Rizzo & Krieger, 1971;Gallagher, Yoshida, Roffwarg et al 1973), rhesus monkeys (Quabbe, Gregor, Bumke-Vogt & Härdel, 1982), sheep (Fulkerson & Tang, 1979) and cattle (Thun, Eggenberger, Zerobin et al 1981). In each of these studies, hormonal profiles were characterized in blood samples collected at a frequency of every 5 to 30 min throughout the day.…”