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Unacylated ghrelin, leptin, and appetite display diurnal rhythmicity in lean Adults
Templeman, Iain Smith, Harry A. Walhin, Jean-Philippe Middleton, Benita Gonzalez, Javier T. Karagounis, Leonidas G. Johnston, Jonathan D. Betts, James A.
Templeman, Iain
Smith, Harry A.
Walhin, Jean-Philippe
Middleton, Benita
Gonzalez, Javier T.
Karagounis, Leonidas G.
Johnston, Jonathan D.
Betts, James A.
Abstract
Constant routine and forced desynchrony protocols typically remove the effects of behavioral/environmental cues to examine endogenous circadian rhythms, yet this may not reflect rhythms of appetite regulation in the real world. It is therefore important to understand these rhythms within the same subjects under controlled diurnal conditions of light, sleep, and feeding. Ten healthy adults (9 M/1 F, means ±SD: age, 30 ± 10 yr; body mass index, 24.1 ± 2.7 kg·m−2) rested supine in the laboratory for 37 h. All data were collected during the final 24 h of this period (i.e., 0800–0800 h). Participants were fed hourly isocaloric liquid meal replacements alongside appetite assessments during waking before a sleep opportunity from 2200 to 0700 h. Hourly blood samples were collected throughout the 24-h period. Dim light melatonin onset occurred at 2318 ± 46 min. A diurnal rhythm in mean plasma unacylated ghrelin concentration was identified (P = 0.04), with the acrophase occurring shortly after waking (0819), falling to a nadir in the evening with a relative amplitude of 9%. Plasma leptin concentration also exhibited a diurnal rhythm (P < 0.01), with the acrophase occurring shortly after lights-out (0032 h) and the lowest concentrations at midday. The amplitude for this rhythm was 25%. Diurnal rhythms were established in all dimensions of appetite except for sweet preference (P = 0.29), with both hunger (2103 h) and prospective food consumption (1955 h) reaching their peak in the evening before falling to their nadir shortly after waking. Under controlled diurnal conditions, simultaneous measurement of leptin, unacylated ghrelin, and subjective appetite over a 24-h period revealed rhythmicity in appetite regulation in lean, healthy humans.
Keywords
appetite, circadian rhythms, diurnal, ghrelin, leptin
Date
2021
Type
Journal article
Journal
Journal of Applied Physiology
Book
Volume
130
Issue
5
Page Range
1534-1543
Article Number
ACU Department
Mary MacKillop Institute for Health Research
Faculty of Health Sciences
Faculty of Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
Published as green open access
License
File Access
Controlled
Open
Open