title: Diurnal rhythms of plasma GLP-1 levels in normal and overweight/obese subjects: lack of effect of weight loss.
abstract: Food intake is regulated by not only neurohormonal, but also social, educational, and even cultural factors. Within the former, there is a complex interaction between orexigenic (ghrelin) and anorexigenic (glucagon-like peptide-1 (GLP-1)) factors in order to adjust the food intake to caloric expenditure; however, the number of subjects that are unable to properly balance appetite and body weight is increasing continuously. A loss of circadian or diurnal coordination of any of these factors may be implied in this situation. Special attention has retrieved GLP-1 due to its usefulness as a therapeutic agent against obesity and related alterations. Thus, the objective of the present study was to compare GLP-1 diurnal synthesis between normal weight and overweight/obese subjects, and to evaluate whether weight loss can restore the synthesis rhythms of GLP-1. Three groups of 25 subjects were divided attending to their body mass index (BMI) in normal weight, overweight, or obese subjects. Diurnal (5 points) GLP-1 levels were analyzed. Secondly, an intervention (behavioral-dietary treatment) study was conducted to analyze the effect of weight loss on plasma GLP-1 concentrations. Our results showed that baseline GLP-1 level was significantly lower in normal weight subjects (p = 0.003); furthermore, our cosinor analysis revealed a higher amplitude (p = 0.040) and daily GLP-1 variation (47%) in these subjects. In fact, our ANOVA data showed a lack of rhythmicity in overweight/obese patients. Weight loss was not able to restore a diurnal rhythm of plasma GLP-1 levels. In summary, the present work shows a disruption of diurnal GLP-1 levels in overweight/obese subjects, which worsen as body fat progresses. The attenuation of the GLP-1 synthesis rhythms may be important to understand the impairment of food intake regulation in overweight/obese subjects.
authors.affiliation: Department of Nursing. Faculty of Nursing, Catholic University of Murcia, Campus de Guadalupe, s/n, 30107, Murcia, Spain.
authors.forename: Joaquín Santiago
authors.initials: JS
authors.lastname: Galindo Muñoz
authors.forename: Diana
authors.initials: D
authors.lastname: Jiménez Rodríguez
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Hernández Morante
mesh_terms: D000328:Adult; D031204:Caloric Restriction; D016022:Case-Control Studies; D002940:Circadian Rhythm; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D006801:Humans; D008297:Male; D009765:Obesity / Q000097:blood*; D050177:Overweight / Q000097:blood*; D015431:Weight Loss; D055815:Young Adult
chemical_list: D052216:Glucagon-Like Peptide 1