Leptin, Human

VPIQKVQDDT KTLIKTIVTR INDISHTQSV SSKQKVTGLD FIPGLHPILT LSKMDQTLAV YQQILTSMPS RNVIQISNDL ENLRDLLHVL AFSKSCHLPW ASGLETLDSL GGVLEASGYS TEVVALSRLQ GSLQDMLWQL DLSPGC

[1]A sensor (leptin production by adipose cells) monitors the size of the adipose tissue mass. Hypothalamic centers receive and integrate the intensity of the leptin signal through leptin receptors (LRb). Effector systems, including the sympathetic nervous system, control the two main determinants of energy balance-energy intake and energy expenditure^[1]. Recessive mutations in the leptingene are associated with massive obesity in mice and humans, establishing a genetic basis for obesity. Leptin circulates in blood and acts on the brain to regulate food intake and energy expenditure. When fat mass falls, plasma leptin levels fall, stimulating appetite and suppressing energy expenditure until fat mass is restored. When fat mass increases, leptin levels increase, suppressing appetite until weight is lost. This system maintains homeostatic control of adipose tissue mass^[2].|[2]Friedman JM, et al. Leptin and the regulation of body weigh. Keio J Med. 2011;60(1):1-9.