Final answer:
The action of leptin involves decreasing the release of NPY in the hypothalamus, which reduces hunger and promotes satiety. Abnormalities in leptin signaling, like leptin resistance, can contribute to overeating and obesity.
Step-by-step explanation:
A key effect of leptin that results in the inhibition of eating is to decrease the release of NPY in the hypothalamus. Leptin is a hormone released by adipose tissues that promotes satiety by signaling the brain when fat reserves are high, thereby reducing hunger. When the hypothalamus receives elevated levels of leptin, it inhibits the production of neuropeptide Y (NPY), a potent stimulator of hunger, and agouti-related peptide (AGRP), thus reducing the desire to eat.
Leptin plays a crucial role in the regulation of energy balance by inhibiting hunger, which leads to reduced food consumption and potentially helps to prevent excessive weight gain. However, in some cases, such as obesity, there can be a decreased sensitivity to leptin leading to an condition termed leptin resistance, where the satiety signals are not properly recognized, often resulting in overeating.