What is the function of the protein hormone, Leptin?
Previous studies have shown that overweight and obesity in mid-life are associated with poorer cognitive function in the general population and an increased risk of dementia. There has been evidence that leptin exerts additional functions on the brain outside the hypothalamus (a region of the brain that controls body temperature, hunger, and thirst), according to background information in the article. Wolfgang Lieb, M.D., of the Framingham Heart Study, Framingham, Mass., and colleagues examined the relationship between measurements of plasma leptin concentrations and incidence of dementia and Alzheimer disease (AD). For this study, plasma leptin concentrations were measured in 785 persons without dementia (average age, 79 years; 62 percent female), who were in the original Framingham study group at the 22nd examination cycle (1990-1994). A subsample of 198 dementia-free survivors underwent volumetric brain magnetic resonance imaging (MRI) between 1999 and 2005, approximately 7.7 years
In addition to being a bio marker for body fat, serum leptin levels also reflect individual energy balance. Several studies have shown that fasting or following a very low calorie diet (VLCD) lowers leptin levels. It might be that on short term leptin is an indicator of energy balance. This system is more sensitive to starvation than to overfeeding. That is, leptin levels do not rise extensively after overfeeding. It might be that the dynamics of leptin due to an acute change in energy balance are related to appetite and eventually to food intake. There is some controversy regarding the regulation of leptin by melatonin during the night. One research group suggested that increased levels of melatonin caused a down regulation of leptin.
Previous studies have shown that overweight and obesity in mid-life are associated with poorer cognitive function in the general population and an increased risk of dementia. There has been evidence that leptin exerts additional functions on the brain outside the hypothalamus (a region of the brain that controls body temperature, hunger, and thirst), according to background information in the article. Wolfgang Lieb, M.D., of the Framingham Heart Study, Framingham, Mass., and colleagues examined the relationship between measurements of plasma leptin concentrations and incidence of dementia and Alzheimer disease (AD). For this study, plasma leptin concentrations were measured in 785 persons without dementia (average age, 79 years; 62 percent female), who were in the original Framingham study group at the 22nd examination cycle (1990-1994). A subsample of 198 dementia-free survivors underwent volumetric brain magnetic resonance imaging (MRI) between 1999 and 2005, approximately 7.7 years
In addition to being a bio marker for body fat, serum leptin levels also reflect individual energy balance. Several studies have shown that fasting or following a very low calorie diet (VLCD) lowers leptin levels. It might be that on short term leptin is an indicator of energy balance. This system is more sensitive to starvation than to overfeeding. That is, leptin levels do not rise extensively after overfeeding. It might be that the dynamics of leptin due to an acute change in energy balance are related to appetite and eventually to food intake. There is some controversy regarding the regulation of leptin by melatonin during the night. One research group suggested that increased levels of melatonin caused a down regulation of leptin. However, in 2004, Brazilian researchers found that in the presence of insulin, “melatonin interacts with insulin and up regulates insulin-stimulated leptin expression”, therefore causing a decrease in appetite whilst sleeping Sources:
