Final answer:
The satiety hormone is called leptin. It is secreted by adipose tissues and works to signal the brain to reduce appetite, thereby regulating energy balance and playing a crucial role in body weight management. The correct option is A leptin.
Step-by-step explanation:
The satiety hormone is called leptin. This protein hormone is secreted by adipose tissues in response to food consumption and promotes the feeling of fullness, which we term satiety. Leptin functions by signaling the brain to reduce appetite and thereby inhibit further eating, playing a crucial role in regulating energy balance within the body.
It acts as a messenger from the body's fat stores to the brain, letting the brain know how much energy is available and if it's necessary to eat more or stop eating. This hormone is a key factor in the pathophysiology of obesity, where an individual may become resistant to leptin, leading to an inability to feel satiated and contributing to overeating.
Other hormones are also involved in hunger and satiety, including luteinizing hormone (LH), which is important for ovulation and testosterone production, and melatonin, which is related to sleep cycles rather than satiety. For comparison, insulin is another hormone that regulates blood glucose and is not specifically linked to the feeling of satiety.