Chapter 19: Problem 18
Which of the following is not an adipokine? a. leptin c. ghrelin b. adiponectin d. tumor necrosis factor alpha
Short Answer
Expert verified
The only option that is not an adipokine is 'c. ghrelin'.
Step by step solution
01
Understanding adipokines
Adipokines are a type of protein that is secreted by adipose tissue. They are involved in various metabolic processes like appetite regulation, inflammation, and insulin sensitivity.
02
Identifying the adipokines among the options
Leptin, Adiponectin, and Tumor Necrosis Factor Alpha are all types of adipokines.
03
Identifying the non-adipokine among the options
Ghrelin, while a hormone involved in hunger signals and appetite regulation, is not produced by adipose tissue but rather is mainly produced in the stomach. Therefore, even though it is associated with metabolic processes, it is not considered an adipokine.
04
Confirming the answer
The only option that is not an adipokine is ghrelin. So, the answer is 'c. ghrelin'.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Leptin
Leptin is often referred to as the 'satiety hormone' or 'fat controller.' It's a hormone made by adipose cells that helps to regulate energy balance by inhibiting hunger. Leptin counteracts the action of ghrelin, the 'hunger hormone.'
When fat mass decreases, the level of plasma leptin falls, thus stimulating appetite. Conversely, when fat mass increases, so do leptin levels, which in turn reduces food consumption. However, leptin's function is not just to stop us from eating. It also plays a critical role in regulating energy expenditure, fertility, and immune functions.
Leptin resistance, a condition in which the body does not respond adequately to leptin signals, is associated with obesity and can make weight loss challenging. Understanding leptin's role can provide insights into the mechanisms of obesity and potential treatments for weight management.
When fat mass decreases, the level of plasma leptin falls, thus stimulating appetite. Conversely, when fat mass increases, so do leptin levels, which in turn reduces food consumption. However, leptin's function is not just to stop us from eating. It also plays a critical role in regulating energy expenditure, fertility, and immune functions.
Leptin resistance, a condition in which the body does not respond adequately to leptin signals, is associated with obesity and can make weight loss challenging. Understanding leptin's role can provide insights into the mechanisms of obesity and potential treatments for weight management.
Adiponectin
Adiponectin, unlike leptin, actually increases with weight loss and has anti-inflammatory properties. It plays a significant role in the process of lipid metabolism and insulin sensitivity. Higher levels of adiponectin have been linked to a lower risk of type 2 diabetes and cardiovascular diseases.
Adiponectin enhances the body's ability to break down fats and improve glucose uptake by cells, acting as a metabolic regulator. Because of these functions, adiponectin is considered to have protective effects against metabolic syndrome, which includes conditions like diabetes, obesity, and heart disease.
Research suggests that increasing adiponectin levels can have therapeutic effects for metabolic diseases, highlighting the hormone's potential as a target for drug development.
Adiponectin enhances the body's ability to break down fats and improve glucose uptake by cells, acting as a metabolic regulator. Because of these functions, adiponectin is considered to have protective effects against metabolic syndrome, which includes conditions like diabetes, obesity, and heart disease.
Research suggests that increasing adiponectin levels can have therapeutic effects for metabolic diseases, highlighting the hormone's potential as a target for drug development.
Tumor Necrosis Factor Alpha (TNF-α)
Tumor Necrosis Factor Alpha (TNF-α) is an inflammatory cytokine produced by various cells, including adipose tissue. It plays a crucial role in the inflammatory response and has been implicated in a variety of diseases, including autoimmune disorders, cancer, and insulin resistance.
In the context of adipokines, TNF-α is known to contribute to the development of insulin resistance, which can lead to type 2 diabetes. Its levels tend to be higher in individuals with obesity. TNF-α not only affects cell signaling and inflammation but also participates in the process of apoptosis, or programmed cell death, which is vital for maintaining tissue homeostasis.
Due to its significant role in inflammation and metabolic disorders, TNF-α is a target for certain anti-inflammatory medications used in the treatment of autoimmune diseases.
In the context of adipokines, TNF-α is known to contribute to the development of insulin resistance, which can lead to type 2 diabetes. Its levels tend to be higher in individuals with obesity. TNF-α not only affects cell signaling and inflammation but also participates in the process of apoptosis, or programmed cell death, which is vital for maintaining tissue homeostasis.
Due to its significant role in inflammation and metabolic disorders, TNF-α is a target for certain anti-inflammatory medications used in the treatment of autoimmune diseases.
Ghrelin
Ghrelin is widely known as the 'hunger hormone.' It is produced predominantly in the stomach and, to a lesser extent, in the small intestine, pancreas, and brain. Ghrelin stimulates appetite and increases food intake, and it also promotes the release of growth hormone from the pituitary gland.
Ghrelin levels increase before meals and decrease after meals. It works in concert with leptin: while ghrelin encourages appetite and the accumulation of body fat, leptin signals satiety and prompts the body to burn fat. Ghrelin also has protective effects on the cardiovascular system and plays a role in the regulation of sleep and mood.
Understanding ghrelin's mechanisms is essential for developing obesity treatments, as modulating this hormone could help control hunger and reduce food intake. However, as stated in the exercise, ghrelin is not classified as an adipokine because it's not produced by adipose tissue.
Ghrelin levels increase before meals and decrease after meals. It works in concert with leptin: while ghrelin encourages appetite and the accumulation of body fat, leptin signals satiety and prompts the body to burn fat. Ghrelin also has protective effects on the cardiovascular system and plays a role in the regulation of sleep and mood.
Understanding ghrelin's mechanisms is essential for developing obesity treatments, as modulating this hormone could help control hunger and reduce food intake. However, as stated in the exercise, ghrelin is not classified as an adipokine because it's not produced by adipose tissue.
