Melatonin: A Silent Regulator of the Glucose Homeostasis

Abstract

In the human organism, the circadian regulation of carbohydrates metabolism is essential for the glucose homeostasis and energy balance. Unbalances in glucose and insulin tissue and blood levels have been linked to a variety of metabolic disorders such as obesity, metabolic syndrome, cardiovascular diseases and type 2 diabetes. Melatonin, the pineal hormone, is the key mediator molecule for the integration between the cyclic environment and the circadian distribution of physiological and behavioral processes and for the optimization of energy balance and body weight regulation, events that are crucial for a healthy organism. This chapter reviews the interplay between melatonin modulatory physiological effects, glucose homeostasis and metabolic balance, from the endocrinology perspective. The tremendous effect of melatonin in the regulation of metabolic processes is observed from the chronobiology perspective, considering melatonin as a major synchronizer of the circadian internal order of the physiological processes involved in energy metabolism.

Sirtuins and Melatonin: Linking Chronobiology to Inflammation and Aging

“…The imbalance of melatonin, which is one of the master regulators of the internal clocks in humans, is clearly associated with an increased risk of diseases, correlated with impaired sleep and aging-associated pathology, mainly cardiovascular, metabolic, and neurodegenerative disease [35][36][37][38][39][40][41][42].…”

Insights Into Chrononutrition: The Innermost Interplay Amongst Nutrition, Metabolism and the Circadian Clock, in the Context of Epigenetic Reprogramming

“…There are associated with an extensive range of pathologies, including metabolic syndrome, obesity, diabetes, cardiovascular diseases, tumorigenesis and neurodegeneration. All organisms rely on their communication with environmental sensors, their interaction with outlining factors, competing with external challenges and their capacity to predict them and simultaneously adapt to new settings dictates how organisms overpass the intricacy states [8,20,34]. The human organism relies on carbohydrates, lipids, and proteins as principal components of food that serve as energetic molecules.…”

“…Muscle β-oxidation of fatty acids stops the transformation of pyruvate to acetyl CoA; thus pyruvate, lactate, and alanine are oriented towards the liver for their transformation into glucose. Another secondary hepatic source of glucose is glycerol derived from the breakdown of triacylglycerols [20,43,45,84]. The significant synthesis of ketone bodies begins after three days of starvation, the liver generating high levels of acetoacetate and β-3-hydroxybutyrate owing to its turn over from acetyl CoA which increases considerably as the Krebs cycle is ineffective in oxidizing all the acetyl molecules from the degradation of fatty acids.…”

“…Another important aspect is represented by it is own and extremely powerful antioxidant mechanism driven concomitantly in order maintain a steady-state oxidative status, due to the high level of reactive oxygen species acquired throughout the intense cellular processes. Physiological or pathological states related with melatonin synthesis decline, like ageing, shift work or environmental lighting during the night and diabetes, conduct to a series of pathological consequences which are mainly clustered in the metabolic syndrome components, like obesity, insulin resistance, cardiovascular malfunction, and hypertension [15,20].…”

Introductory Chapter: Melatonin, the Integrative Molecule within the Human Architecture

“…Melatonin also exerts different effects on the glucose metabolism, considering various targets: it stimulates glucose uptake in muscle cells by phosphorylation of insulin receptor substrate-1 through MT2 signaling, MT2 receptors are expressed in hepatocytes, and melatonin therapy elevates glucose release from the liver [54].…”