Adiponectin

What is adiponectin?

Adiponectin is a hormone and an adipokine protein that affects several metabolic processes and is mainly known for its insulin-sensitizing and anti-inflammatory effects. Your adipose tissue (body fat) is mainly responsible for producing adiponectin, though other tissues in your body produce it as well.

Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, muscles and other tissues. These signals tell your body what to do and when to do it.

Adipokines (also called adipocytokines) are hormones that your adipose tissue makes that play functional roles in energy and metabolic processes. Metabolic processes (metabolism) are the many chemical reactions inside your body that turn the food (calories) you eat into energy and transport that energy to all your cells.

Lower-than-normal adiponectin levels are associated with several endocrine and metabolic conditions, including:

• Obesity.
• Type 2 diabetes.
• Metabolic syndrome.

Scientists discovered adiponectin in the 1990s, so they’re still learning about it. It may have more functions that they haven’t discovered yet.

Where does adiponectin come from?

Energy-storing cells in your white adipose tissue called adipocytes primarily produce and release adiponectin. White adipose tissue is the main type of fat in your body. It’s beneath your skin (subcutaneous fat), around internal organs (visceral fat) and in your bones (marrowfat).

Other types of cells can produce adiponectin, including skeletal muscle cells (the muscles that help you move), heart muscle cells and endothelial cells — the cells that make up a thin membrane that lines the inside of your heart and blood vessels.

How are adiponectin levels controlled?

Since adiponectin is a relatively new discovery, scientists are still studying it. So far, they’ve found several hormones help control adiponectin levels.

Insulin seems to play a role in the creation (synthesis) of adiponectin, though not all scientists agree on exactly how. Insulin is the hormone your pancreas makes to help regulate your blood sugar (glucose) levels.

The hormones insulin-like growth factor (IGF-1) and growth hormone (GH) regulate adiponectin release in adipose (fat) tissue. Leptin (another adipokine) may also play a role in adiponectin regulation.

What is the function of adiponectin?

Adiponectin plays an important role in several metabolic and cellular functions. Its two main functions deal with insulin sensitization and anti-inflammatory effects.

Adiponectin and insulin sensitivity

Insulin is a hormone your pancreas makes to regulate blood glucose (sugar) levels by lowering them. More specifically, insulin helps glucose in your blood enter your muscle, fat and liver cells so they can use it for energy or store it for later use. Because of this, insulin is essential for life.

Insulin sensitivity refers to your body’s ability to use insulin effectively. The more insulin sensitivity you have, the more easily your body can use insulin and keep your blood glucose levels in a healthy range.

Insulin resistance is the opposite of insulin sensitivity and happens when cells in your muscles, fat and liver don’t respond as they should to insulin. Your pancreas has to pump out more insulin than normal, a condition known as hyperinsulinemia, to overcome the resistance and keep your blood glucose levels in range.

Adiponectin plays a role in insulin sensitivity by:

• Impacting insulin sensitivity in your skeletal muscle (the muscles attached to your bones that help you move) and liver.
• Increasing insulin release from your pancreas.
• Enhancing basal (background) glucose and insulin-stimulated glucose uptake in adipose (fat) tissues.
• Inhibiting (preventing) glucose production in your liver.
• Promoting fatty acid oxidation.
• Promoting fat storage in subcutaneous fat pads instead of visceral fat pads, liver or skeletal muscle. This type of fat storage reduces visceral fat mass and systemic inflammation, with improved glucose and fat metabolism and increased insulin sensitivity.

Adiponectin and inflammation

Inflammation occurs when your immune system sends out cells to fight bacteria or heal an injury. There are two main types of inflammation, including:

• Acute inflammation: This is the necessary response to sudden bodily damage, such as a cut on your arm. To heal the cut, your body sends inflammatory cells to the injury to start the healing process.
• Chronic inflammation: This happens when your body continues sending inflammatory cells even when there’s no outside danger. Many conditions can cause or be affected by chronic inflammation, including rheumatoid arthritis, Type 2 diabetes, heart disease, Alzheimer's disease and cancer.

Adiponectin decreases inflammation in macrophages (a type of white blood cell that surrounds and kills microorganisms), endothelial tissue, muscle cells and epithelial cells. Adiponectin’s anti-inflammatory properties result in the protection of your vascular system, heart, lungs and colon.

What’s the difference between adiponectin and leptin?

Leptin and adiponectin are both hormones, or adipokines, that your adipose tissue makes and releases. Leptin enhances metabolism and reduces appetite.

Like adiponectin, abnormal levels of leptin are associated with obesity. However, while higher adipose tissue (body fat) mass results in elevated leptin levels, a higher body fat mass results in lower adiponectin levels.

What test checks adiponectin levels?

A blood test can check the amount of adiponectin in a blood sample taken from a vein in your arm.

Healthcare providers might order an adiponectin blood test to help diagnose metabolic conditions such as Type 2 diabetes and metabolic syndrome. However, there are other more common tests to diagnose these conditions.

What are normal adiponectin levels?

Normal value ranges for adiponectin levels may vary slightly among different laboratories. Be sure to look at the range of normal values listed on your laboratory report or ask your healthcare provider if you have questions about your results.

Normal adiponectin levels vary based on your sex organs and body mass index (BMI).

Body mass index (BMI) is a screening tool that measures the ratio of your height to your weight. Healthcare providers calculate BMI by using weight in kilograms (kg) divided by the square of height in meters (m2). In most people, BMI relates to body fat, but it’s not accurate in some cases. BMI alone does not diagnose obesity or health. Healthcare providers use BMI and other tools and tests to assess someone’s health status and risks.

In general, normal adiponectin ranges for people assigned male at birth include:

• People with a BMI less than 25: 5 to 37 micrograms per milliliter (ug/mL).
• People with a BMI of 25 to 30: 5 to 28 ug/mL.
• People with a BMI over 30: 2 to 20 ug/mL.

In general, normal adiponectin ranges for people assigned female at birth include:

• People with a BMI less than 25: 5 to 37 ug/mL.
• People with a BMI of 25-30: 4 to 20 micrograms per milliliter (ug/mL).
• People with a BMI over 30: 4 to 22 ug/mL.

What conditions are associated with abnormal adiponectin levels?

Several health conditions are associated with abnormal adiponectin levels, including:

• Obesity and underweight.
• Insulin resistance.
• Atherosclerosis.
• Lipodystrophy.

Most of these conditions are associated with lower-than-normal adiponectin levels.

Adiponectin and obesity

People with obesity have decreased levels of adiponectin. On the other hand, adiponectin levels are higher than normal in people who are severely underweight, such as people who have anorexia nervosa or malnutrition. In general, the more body fat someone has, the lower their adiponectin levels are, and vice versa. Weight loss in people with obesity results in increased adiponectin levels.

Adiponectin and insulin resistance

Since adiponectin aids in insulin sensitivity, people who experience insulin resistance typically have low levels of adiponectin. Insulin resistance happens when cells in your body don’t respond to insulin as they should, which results in excess insulin release (hyperinsulinemia).

Insulin resistance can result in prediabetes, Type 2 diabetes and gestational diabetes. While insulin resistance is often associated with obesity, people can have insulin resistance without having obesity. And people who have insulin resistance without obesity usually have low adiponectin levels as well. This suggests that there may be a genetic factor involved with insulin resistance and adiponectin.

Adiponectin and atherosclerosis

Atherosclerosis is a condition that happens when plaque builds up on the inside walls of your arteries. Plaque is a sticky substance made of fat, cholesterol, calcium and other substances. As plaque builds up, your arteries become hard and narrow.

Since adiponectin has anti-inflammatory effects that help protect your heart and blood vessels, low levels of adiponectin can contribute to atherosclerosis and other cardiovascular issues, such as heart attacks (myocardial infarctions).

Adiponectin and lipodystrophy

Lipodystrophy is a group of rare syndromes that cause you to have a lack of fat (adipose tissue) in some parts of your body, while having excess amounts of fat in other areas, including on organs like your liver. A person can be born with lipodystrophy or develop it later in life.

Congenital (from birth) and HIV-related lipodystrophies are associated with low levels of adiponectin. This is likely because adiponectin plays a role in how your body stores fat.

Is there treatment for abnormal adiponectin levels?

A natural treatment to improve adiponectin levels is consistent exercise and healthy weight loss. Always talk to your healthcare provider before making drastic changes to your diet or exercise routine.

Medications such as metformin and thiazolidinediones, which providers prescribe to help treat Type 2 diabetes, result in an increase in adiponectin levels. Scientists are currently working on developing drugs that can mimic the effects of adiponectin for various tissues to treat chronic inflammatory conditions.

A note from Cleveland Clinic

Adiponectin has several important functions. Since it’s a relatively new discovery, scientists are still working to learn more about it, including how synthetic forms of it could help treat certain conditions. If you have a metabolic condition, such as obesity or Type 2 diabetes, you might hear your healthcare provider mention adiponectin. If you’re ever unfamiliar with a term your provider uses, feel free to ask them what it means. They are there to help you.