Leptin is a circulating hormone that is produced by fat cells and plays a role in body metabolism and obesity.It normally binds to receptors in the brain and inhibits appetite.Studies have demonstrated that when obese mice that are leptin deficient are injected with leptin they quickly lose their excess weight.Interestingly,however,many overweight people have high levels of leptin in their bloodstream.Why do you think that the high levels of leptin in obese individuals are insufficient to curb their appetite?
A)Paracrine signaling may be disrupted in obese people with high levels of leptin.
B)Obese people who have high levels of leptin may have a leptin receptor with decreased sensitivity.
C)The form of leptin released by obese people may lack protein kinase activity.
D)In obese people with high levels of leptin,the leptin is a non-functional second messenger.

Question

Quizplus · Accepted Answer

Obese people who have high levels of leptin may have a leptin receptor with decreased sensitivity. This condition is known as leptin resistance, where the brain becomes less responsive to the signals sent by leptin, hence the inability to curb appetite. As a result, even with high levels of leptin in their bloodstream, obese individuals continue to overeat and gain weight.

Leptin Is a Circulating Hormone That Is Produced by Fat