Resistin is a peptide hormone. Medical researchers view it as a potential link between obesity and diabetes mellitus (type 2).
What is resistin?
Resistin is a recent discovery: it was only in 2001 that researchers became aware of the hormone when they conducted a study on insulin resistance. Another name for resistin in English is adipocyte-specific secretory factor (ADSF), because it appears to cause insulin resistance as a result of obesity. Obesity or obesity is the medical term for high levels of overweight, which they use the body mass index (BMI) to determine. The formula for BMI relates an individual’s height and weight. Although critics repeatedly describe BMI as unreliable, it is generally a good guide: General health risks, individual disease factors and complex diseases have been linked to BMI in countless studies. Experts define simple obesity as a BMI of at least 25 in people over the age of 18 who do not engage in competitive sports or bodybuilding, for example. Obesity is present above a BMI of 30 and correlates with numerous health problems – including type 2 diabetes. Diabetes represents one of the most common complications of overweight and obesity and can significantly reduce quality and expectancy of life. The hormone resistin, which the human body produces in response to obesity and poor nutrition, triggers cells to become resistant to the hormone insulin, which regulates blood glucose levels. As a result, the characteristic symptoms of diabetes manifest.
Function, effects, and roles
Researchers became aware of the possible link between resistin and type 2 diabetes when the peptide hormone induced insulin resistance in mice in a U.S. study. Resistin owes its name to this resistance. Insulin is a hormone produced by the pancreas. It lowers the blood glucose level and thereby regulates the energy supply of the human body. When food is consumed, the blood glucose level rises in the form of glucose. However, strong fluctuations would lead to a physiological imbalance; the organism depends on having as much energy as possible available continuously. For this reason, the body counteracts the rise in blood glucose: The pancreas releases insulin. However, the insulin does not itself react with the glucose in the blood. Instead, it acts like a key and ensures that the body’s cells absorb more glucose. This causes the blood glucose level to drop back to its normal level. However, in the case of insulin resistance in diabetes, the cells of the body do not respond to the signal from insulin any more or respond more weakly than in a healthy person. In particular, the cells of the fatty tissue, muscles and liver are typically affected. The blood glucose level rises; but instead of flowing into the cells, the glucose remains in the blood and is thus not available to the body as energy. If left untreated, insulin resistance can, in extreme cases, lead to death by starvation – because although the affected person theoretically consumes sufficient food, the organism is unable to metabolize it. According to recent research, the peptide hormone resistin causes this insulin resistance.
Formation, occurrence, properties, and optimal levels
The human body is capable of forming resistin itself. The fatty tissue of the organism is responsible for this. As far as is known, resistin is found only in humans and other higher mammals. The molecule of the peptide hormone consists of 90 amino acids. Amino acids are units of protein; they consist of a central carbon atom (C) to which an amino group (NH2), a carboxyl group (COOH), a single hydrogen atom (H), an α-carbon atom, and a residual group are attached. The residual group is unique to each of the 20 amino acids. Proteins serve not only as building blocks for hormones such as resistin but also for structures inside and outside cells and for enzymes. They are therefore essential for life. The genetic code determines the order in which the various amino acids form a chain.Due to their physical properties, these amino acid chains fold in three-dimensional space, giving them their characteristic shape.
Diseases and disorders
For a long time, medicine has known about the connection between overweight or obesity on the one hand and type 2 diabetes on the other. Current evidence suggests that resistin may provide the missing link that explains the precise mechanisms behind this association. Diabetes is a chronic metabolic disease, which is also colloquially referred to as diabetes. Various causes can contribute to its development; insulin resistance is one of them. Scientists have been able to observe this effect in animal experiments. In 2001, Steppan and colleagues conducted a study with mice. They injected the animals with resistin and observed the effects under controlled conditions in the laboratory They also demonstrated that drugs used to treat diabetes led to lower concentrations of resistin. The exact mechanisms are still unclear, but raise hopes for new and more effective long-term therapies for diabetes. Until some time ago, experts and lay people predominantly used the term “adult-onset diabetes” as a synonym for type 2 diabetes. However, fewer and fewer people are using this term. One important reason for this is the widespread prevalence of this form of diabetes, which has now reached epidemic proportions worldwide. It affects people of all ages and correlates with body weight. Initially, diabetes often becomes noticeable through enormous thirst. Other symptoms include fatigue, visual disturbances, feelings of weakness and increased infections.
