Circadian Rhythms of Plasma Renin Activity and Aldosterone: Changes Related to Age, Sex, Recumbency and Sodium Restriction. Chronobiologic Specification for Reference Values

Abstract

Plasma renin activity (PRA) and aldosterone (PA) levels are characterized by a circadian rhythmicity (CR). The present study revealed that this rhythmicity is influenced by several factors including posture, sodium intake and age. Time-qualified PRA and PA reference intervals can reduce the incidence of false positives and false negatives in a diagnostic work-up. The circadian rhythmicity of PRA and PA have been quantified in relation to posture, sodium intake and age. The cosinor procedure has been applied to quantify the properties of the circadian rhythmicity under these conditions. Chronograms and circadian parameters can be used to optimize the use of PRA and PA measurements in clinical practice. The chronobiological specification of reference values for PRA and PA is of valuable importance since the assessment of PRA and PA circadian rhythmicity has a diagnostic interest for a certain type of clinical disorder. It should be noted that several studies have described circannual variations for renin and aldosterone. The next step in the optimation of laboratory time-qualified reference values is the assessment of changes induced by the deterministic factors on a circannual domain.

Chronobiology and Pharmacologic Modulation of the Renin–Angiotensin–Aldosterone System in Dogs: What Have We Learned?

“…Our results are consistent with previous investigations in dogs , horses (Clarke et al 1978(Clarke et al , 1988, and humans (Cugini et al 1981(Cugini et al , 1985, which underlines the similarity of body fluid homeostasis in mammals. A cosine model with a fixed 24-h period was found to fit the periodic variations of RA, BP, urinary aldosterone, and potassium excretion well, as suggested by the quality of the model diagnostics.…”

“…Studies have been performed under (i) sodium restriction (Cugini et al 1981(Cugini et al , 1985, (ii) episodic vs. continuous feeding (Blair-West and Brook 1969;Clarke et al 1978Clarke et al , 1988, and (iii) fasting conditions (Cugini et al 1987). In contrast, the impact of timed feeding on the chronobiology of the renin cascade remains controversial.…”

“…In mammals, the circadian clock influences many physiological and behavioral variables including locomotor activity, body temperature, and heart rate (Reppert and Weaver 2002;Van Esseveldt et al 2000). Peptides of the renin-angiotensin cascade oscillate with a circadian periodicity in humans (Cugini et al 1981(Cugini et al , 1984(Cugini et al , 1985(Cugini et al , 1986(Cugini et al , 1987Kawasaki et al 1990), and data from telemetry monitoring have consistently demonstrated that BP had a reproducible diurnal rhythm, with highest levels measured in the morning and lowest values around midnight (Staessen et al 1992;Smolensky and Haus 2001). Several factors have been shown to influence day-night variations of the systemic RAAS, including alterations in posture (Muller et al 1958), sleep cycles (Brandenberger et al 1985(Brandenberger et al , 1994, and age (Cugini et al 1985).…”

Role of Atrial Natriuretic Peptide in Nocturnal Polyuria in Elderly Males

“…Both renin and aldosterone have a circadian rhythm and in recumbent subjects renin has an acrophase between 2 a.m. and 8 a.m. [18] and aldosterone has an acrophase between 6 a.m. and 8 a.m. [19]. Both are strongly influenced by posture [19][20][21] and ageing [22][23][24][25][26]. ANP lowers the renin secretory rate [27] as well as inhibiting aldosterone secretion [28] and an inverse relationship therefore exists between ANP and both renin and aldosterone.…”

Chronobiological Evidence for an Uncoupling of the Na,K-ATPase to Aldosterone in Normal Renin Hypertension

“…The sampling scheme is based on nonequidistant time points, a protocol validated for the investigation of the circadian rhythmicity of plasma renin activity (PRA) and plasma aldosterone (PA) in normotensives and hypertensives [14,15].…”